APPEAL COURT, HIGH COURT OF JUSTICIARY
 HCJAC 114
Appeal No: XC328/13
OPINION OF THE COURT
delivered by LORD MENZIES
APPEAL UNDER THE CRIMINAL PROCEDURE (SCOTLAND) ACT 1995, SECTIONS 108 AND 110
HER MAJESTY'S ADVOCATE
GARY ANDREW McCOURT
Appellant: Thomson, Solicitor General, QC AD; Crown Agent
Respondent: Kerrigan QC; Fairbairn & Co
25 September 2013
 On 8 April 2013, after a trial at Edinburgh Sheriff Court, a jury convicted the respondent by a majority verdict of causing death by driving a motor car without due care and attention. The charge, of which the respondent was convicted, was in the following terms:
"on 9 August 2011 on a road or other public place, namely Portobello Road, Edinburgh at its junction with Craigentinney Avenue, Edinburgh, you GARY ANDREW MCCOURT did cause the death of Audrey Fyfe, born 14 April 1936, then residing at 22 Coillesdene Crescent, Edinburgh by driving a mechanically propelled vehicle, namely motor car registered number KY53 YSL without due care and attention or without reasonable consideration for other persons using the road or public place in that you did cause your motor car to collide with a pedal cycle, then being ridden by the said Audrey Fyfe, whereby she fell to the ground, striking her head and died on 11 August 2011 as a result of injuries sustained; CONTRARY to the Road Traffic Act 1988, Section 2B."
 On 3 May 2013 the sheriff proceeded to sentence the respondent. At that time he had before him a Criminal Justice Social Work Report, three victim statements, and a schedule of the respondent's previous convictions. This schedule disclosed that the respondent had been convicted in June 1986 at Edinburgh High Court of a contravention of section 1 of the Road Traffic Act 1972 (causing death by reckless driving), in respect of which he was sentenced to imprisonment for one year and disqualified from driving for ten years. Having heard the solicitor for the respondent in mitigation, the sheriff imposed a sentence which comprised a Community Payback Order with a requirement that the respondent undertake 300 hours unpaid work (being the maximum available) within a period of twelve months, disqualified him from holding and obtaining a driving licence for five years and until he passes the extended test of competence to drive, and ordered endorsement of his driving licence. The Crown has appealed against this sentence as being unduly lenient.
The circumstances of
 In his report to this court the trial sheriff set out the evidence about the circumstances of the collision as follows:
"At approximately 6:30pm on 9 August 2011 the respondent was driving a motor car westwards on Portobello Road, Edinburgh. The deceased, Mrs Audrey Fyfe, was riding a bicycle eastwards on Portobello Road. Although other eye witnesses were able to testify about the immediate aftermath, including Mrs Fyfe's fall, and although a police accident reconstruction expert drew certain inferences, the respondent was the only eye witness who was able to testify directly about the collision between his car and Mrs Fyfe's bicycle.
The respondent intended to turn right (approximately northwards) into Craigentinney Avenue, which joins Portobello Road on its north side. He testified that he, 'slowed down to a crawl or stopped' and 'slowed down, more or less stopped' at the junction, to allow an eastbound bus to pass by. In the course of the trial the Crown attempted to prove that no such bus passed the junction at the material time, but the evidence was inconclusive. I have no way of knowing whether or not the jury accepted that part of the respondent's testimony.
In any event, the respondent testified that he moved off and began to turn right:
'I turned right after the bus had passed'; 'I turned to my right as the bus went past.'
His speed was approximately 5 to 10 mph. He deponed that:
'As I started to accelerate I realised a cyclist was going across the lane, so I braked and swerved to the left.'
He did not think that his vehicle had made contact with the cycle or cyclist. He did not hear or feel any contact.
'I seen the cyclist go by me and slightly wobble and cycle on and fall over intae Craigentinney Avenue ...'
In cross-examination the respondent was asked if he had looked to his right. The following exchanges took place:
Q. Did you look to your right?
A. As I turned.
Q. Not before?
A. Not before. I was concentrating on manoeuvring in the middle of the road and watching the bus straight ahead of me.
Q. The bus was your principal focus?
A. Yes ...
Q. You only looked after you started to drive forward and to the right?
Q. You agree that you didn't look before you started your manoeuvre?
A. I looked to the right, to turn right, as I was manoeuvring.
Q. Had you looked right before starting to manoeuvre you'd have been alerted to the fact that Mrs Fyfe was on a bicycle, crossing the junction? Do you agree?
Q. Had you had been aware, you would not have carried out your manoeuvre?
A. No. [which I took to mean 'Yes'] ...
Q. You accept that you clipped her back wheel?
Q. That caused Mrs Fyfe to wobble?
Q. And ultimately she fell to the ground?
A. She cycled on, and fell.
Other witnesses spoke to Mrs Fyfe falling to her right, still astride the cycle, and to her head striking the roadway. It was obvious that she had sustained a serious head injury. She was not wearing a safety helmet. Her daughter, Mrs Linda Hamilton, deponed that Mrs Fyfe never wore a safety helmet: she liked to feel the wind in her hair.
PC Stephen Wilson, an accident reconstruction expert, produced a collision investigation report in which he opined that the markings and the damage to the car and the bicycle suggested a subtle impact that caused the rider of the cycle to lose control and fall. His undisputed conclusion was to the effect that, by inference from damage to the car and cycle, the front offside of the respondent's car struck the rear wheel and offside pannier of the bicycle. The damage was very slight, therefore speed on impact was low and speed was not a contributory factor. From the position of a scratch on the road surface made by the cycle's offside pedal guard, PC Wilson concluded that after the collision the cyclist continued in the same direction of travel for 7 feet or more, lost her balance, and fell to her right. Contact between the car and bicycle must have been minimal. The accused's assertion that he swerved to his left before the collision fitted with the damage and marks at the scene. His version of events (i.e. seeing the cyclist as he was turning and swerving to his left before the collision) was consistent with PC Wilson's objective findings.
In re-examination PC Wilson deponed that the respondent must have had full vision of the bicycle through the front windscreen of the car prior to the collision. The following exchange took place:
Q. Could the bus have obscured the cyclist immediately before the accused began to turn?
A. There is that possibility. If a vehicle was turning and struck the rear wheel of the bike with the front offside corner, the bike would have been travelling therefore the bike would have been in view through the front window prior to impact.
The Crown and defence entered into a lengthy joint minute of agreement, including agreement concerning the medical evidence and cause of death. The agreed medical cause of death was:
'1a Head injury
1b Road traffic collision (cyclist)'
While preparing this report I noted that paragraph 12 of the joint minute is in these terms:
'on 17 August 2011 a post mortem examination took place at the Edinburgh City Mortuary to establish Audrey Fyfe's cause of death. The examination confirmed that Audrey Fyfe died as a result of a head injury as a result of a road traffic collision in which she was struck by a vehicle while cycling.'
In fact Mrs Fyfe and the respondent's vehicle never came into contact. Clearly there is a drafting error in the joint minute that was not noticed by me or by the parties during the trial."
 The sheriff in his report sets out the plea in mitigation advanced on behalf of the respondent. The respondent's solicitor observed that the respondent was aged 49 and lived with his partner of 26 years and their teenage child. As a result of this tragic accident the respondent has become unemployed. The Criminal Justice Social Work Report was generally positive and identified the risk of reoffending as low and no imminent risk of serious harm. The respondent had expressed genuine remorse for the tragic result of his inattention and its impact on the Fyfe family. The respondent's relevant previous conviction was some 27 years ago, and apart from a breach of the peace in 1993 the respondent had not come before the courts since. Applying the Definitive Guideline "Causing Death by Driving" issued in July 2008 by the Sentencing Guidelines Council in England it was submitted that there were no aggravating factors and that the starting point was "Community Order, low to high"
 It is to be noted that the sheriff has not recorded that it formed any part of the plea in mitigation that Mrs Fyfe was not wearing a safety helmet, nor was any evidence led as to what difference, if any, it might have made to the outcome had she been wearing a cycle helmet at the time of the accident.
 The sheriff noted that this court had observed that it is appropriate in cases involving charges of causing death by dangerous driving or careless driving for sentencers in Scotland to have regard to the Definitive Guideline referred to above - see HM Advocate v Noche  HCJAC 108 at paragraph . He observed that the factor that primarily determines the starting point for sentence is the culpability of the offender, and that in determining the starting point the court is required to evaluate:
(i) The quality of the driving involved; and
(ii) The degree of danger that it foreseeably created.
 In assessing the seriousness of the offence, the sheriff had regard to the five factors listed at paragraph 8 of the Definitive Guideline, namely (1) awareness of risk, (2) effect of alcohol or drugs, (3) inappropriate speed of vehicle, (4) seriously culpable behaviour of offender, and (5) failing to have proper regard to vulnerable road users. The sheriff reached the view that only the fifth of these factors applied in the present case; Mrs Fyfe was a cyclist and therefore a vulnerable road user. He also held that the respondent's carelessness arose from momentary inattention. As a first step, he therefore placed the respondent's driving in the third (least serious) level of gravity in the table at page 15 of the Definitive Guideline.
 The sheriff then went on to consider aggravating factors. (Although nothing turns on this in the present case, in his report to us the sheriff states that the Guidelines specify seven potential aggravating factors, and quotes from the table at page 11 of the Definitive Guideline. That table relates to a different offence, namely causing death by dangerous driving, in terms of section 1 of the Road Traffic Act 1988. The table applicable to the present case is that to be found on page 15 of the Definitive Guideline.) The sheriff correctly identified that the only additional aggravating factor in the present case was the respondent's previous conviction for a motoring offence, particularly one that involved bad driving. Because of this, and because the third (least serious) level of gravity in the table applies only where there are no aggravating factors, the sheriff observed that the respondent's case must be placed in the first or second level of gravity.
 The sheriff then went on to consider mitigating factors. (Again, in his report to us the sheriff has directed himself to the table on page 11 of the Definitive Guideline, rather than to the table on page 15. However, again nothing turns on this in the circumstances of this case.) The sheriff concluded that only one such factor applied in this case, namely that the actions of the victim contributed to the commission of the offence. He states that he reached this conclusion because "the victim's deliberate decision not to wear a safety helmet contributed significantly to the likelihood of death resulting".
 The sheriff tells us that he also took into account one aspect of personal mitigation, namely remorse. He referred to paragraph 28 of the Definitive Guideline, which is in the following terms:
"Whilst it can be expected that anyone who has caused death by driving would be expected to feel remorseful, this cannot undermine its importance for sentencing purposes. Remorse is identified as personal mitigation in the Guideline and the Council can see no reason for it to be treated differently for this group of offences. It is for the court to determine whether an expression of remorse is genuine; where it is, this should be taken into account as personal mitigation."
 The sheriff observed that the respondent had expressed remorse for causing Mrs Fyfe's death and its impact on her family - eg in the Criminal Justice Social Work Report. He went on to explain his reasoning as follows:
"Being satisfied that his expressions of remorse were genuine, I considered that I was bound to take them into account in sentencing. Moreover the respondent's health has suffered as a result of the offence. At the locus, he was described as being 'in a state of shock' and 'traumatised'. He is showing signs of PTSD and has become clinically depressed, to the extent that he is no longer fit for work.
Having considered the quality of the respondent's driving, the aggravating factor and the mitigating factors, I concluded that the respondent's culpability lay at the lower end of the second level of gravity specified in the Guidelines and I sentenced accordingly."
The grounds of
appeal, and the sheriff's responses to these
 The first ground of appeal is that the sheriff erred in his assessment of the culpability of the respondent in that he attached insufficient weight to both the quality of the respondent's driving which resulted in the fatal collision and to the respondent's previous conviction for causing death by reckless driving.
 The sheriff noted in response that the respondent was guilty of momentary inattention. The result was a low impact, low speed collision with the victim's cycle. A fatal outcome as a result of the degree of danger created by the quality of the respondent's driving was not reasonably foreseeable. Albeit that Mrs Fyfe was a vulnerable road user, he concluded that the quality of the respondent's driving was at the lowest end of the spectrum of carelessness. With regard to the prior conviction he observed that this was some 27 years ago when the respondent was 22 years old, and apart from a breach of the peace some 20 years ago he had not come to the attention of the authorities until now. Moreover, while the prior road traffic conviction could hardly be more serious, the respondent's driving in the present case was at the opposite end of the spectrum of gravity. The sheriff observed in his report:
"Had the quality of the respondent's driving been at the more serious end of the range of carelessness, I would have been entitled to infer that the respondent had not learned his lesson from the prior conviction, imprisonment and disqualification for ten years. But I was not able to do so. In the circumstances, I was not prepared to attach such weight to the prior conviction that imprisonment would have become inevitable in accordance with the sentencing guidelines."
 The second ground of appeal is that the sheriff further erred in attaching undue weight to the evidence that the deceased was not wearing a cycle helmet at the time of the collision. The sheriff stated that he took into account in mitigation of sentence the deceased's not wearing a cycle helmet which in his view played "a very big part" in the fatal outcome. There was no evidence, medical or otherwise, that the absence of a cycle helmet contributed to the death and the sheriff erred in mitigating the respondent's sentence on that account.
 In response, the sheriff explained that he concluded that failure to wear a safety helmet contributed significantly to the death. He noted that paragraph 24 of the Definitive Guideline provides that:
"where the actions of the victim or a third party contributed to the commission of an offence, this should be acknowledged and take into account as a mitigating factor."
 Paragraph 3 of the introduction to the Definitive Guideline states that the death of a person is an element of the offence, so the sheriff considered that the court should take into account any contribution to the death made by the victim. He was of the opinion that it is a matter within judicial knowledge that in low impact, low speed collisions between vehicles and cycles, a safety helmet is likely to be effective in preventing serious or fatal head injury to a cyclist. He observed:
"No doubt that is why rule 59 of the Highway Code states in part:
'Clothing. You should wear
· a cycle helmet which conforms to current regulations, is the correct size and securely fastened'.
In this case the fatal outcome was wholly disproportionate to the quality of the respondent's driving. The deceased lost her balance and fell sideways, still astride her cycle. Her head struck the road surface and she sustained injury to her head that proved to be fatal. In my view, the accident was the very type of incident for which safety helmets are designed to give protection to cyclists' heads. In my opinion, failure to give significant weight to this factor in sentencing would have been wholly unjust and contrary to paragraph 24 of the Guidelines."
 The third ground of appeal is in the following terms:
"The sentence imposed does not adequately reflect the serious nature of the offence and its consequences when considered in light of the respondent's previous conviction for causing death by reckless driving. The quality of the respondent's driving has now resulted in the deaths of two vulnerable road users. It is submitted that in the circumstances of this case, in the absence of exceptional mitigation, a custodial sentence was inevitable and the sheriff erred in concluding that the direct alternative to custody was within the range of appropriate sentences available. Further, it is submitted that given the respondent's previous conviction the period of disqualification imposed was inadequate to protect the public."
 The sheriff responded by stating that he understood very well the gravity of the offence and its consequences. He suggested that this ground of appeal may be summarised thus:
"Where a person convicted of causing death by reckless driving is convicted subsequently of causing death by careless driving, in the absence of 'exceptional mitigation' a custodial sentence is inevitable.
In other words, in such a case the court must take account only of the aggravation (no matter how historical it may be) and of any 'exceptional' mitigation.
In my opinion that approach is fundamentally unsound because it leaves out of account entirely the culpability of the offender, ie the quality of his driving and the degree of danger foreseeably created. As noted above, it is the culpability of the offender that primarily determines the starting point for sentence. Moreover, failure to have regard to the antiquity of the aggravating offence, as well as the significant difference in culpability between it and the current offence would be irrational and unjust".
 The sheriff concluded that disqualification for five years and until the respondent had passed the extended test of competence to drive was sufficient in the circumstances.
Submissions for the Crown
 The Solicitor General accepted that in order for the Crown to succeed in this appeal, it required to satisfy the court that the sheriff's sentence was unduly lenient, as that term was explained by the court in HM Advocate v Bell 1995 SCCR 244. She submitted that in the circumstances of this case that test was met. By way of background, she observed that there was little or no dispute at trial about much of the evidence, many facts having been agreed in a joint minute of agreement. There was good visibility at the time of the accident, there were no weather issues, and the road was marked with red cycle lanes. It was agreed that the respondent's vehicle struck Mrs Fyfe's bicycle, and two days later she died as a result. No issues were taken as to causation, either in evidence or in closing submissions. The cause of the collision was the respondent's failure to look and check that the road was clear of vulnerable road users before he turned to his right. The respondent accepted in evidence that if he had looked, he would have seen Mrs Fyfe. An additional alert was present in the form of the red coloured cycle lane. It was accepted that in principle the sheriff was correct to have regard to the Definitive Guideline, but he erred in the practical application of the Guideline, and as a result his sentence was unduly lenient.
 The Solicitor General divided her submissions into three main chapters, as follows:
(1) The sheriff did not assess appropriately the culpability of the respondent's driving, (a) in terms of the respondent's actions, and (b) in relation to determining their seriousness in terms of the Definitive Guideline (particularly in respect that Mrs Fyfe was a vulnerable road user).
(2) The sheriff erred in the weight he placed on the aggravating factor of the previous conviction.
(3) The sheriff erred in his assessment of mitigatory factors, and in particular in relation to the wearing of a cycle helmet, which was not a matter raised before him in evidence or in submissions.
 With regard to culpability of driving, the central feature must be the quality of driving, and the degree of danger that it foreseeably created - see paragraph 3 of the Definitive Guideline. The sheriff was correct to identify the culpability of the driving as the first question to be considered, but he erred in reaching the conclusion that what the respondent did amounted to momentary inattention and so fell within level three of the table on page 15 of the Definitive Guideline. The respondent failed to look to his right before he began the manoeuvre of turning to his right - he only looked after he had begun the manoeuvre. This was not a momentary inattention but a basic failure of driving.
 The Solicitor General submitted that it was necessary for a sentencer to apply his or her mind to the issue of the culpability or seriousness of the driving at two separate stages in the process of applying the Definitive Guideline. This is because, as is stated in paragraph 3 of the Definitive Guideline, the central feature should be an evaluation of the quality of the driving involved and the degree of danger that it foreseeably created. The Solicitor General submitted that there required to be an evaluation of the quality of driving involved and the degree of danger that it foreseeably created in terms of paragraph 3 of the Definitive Guideline, and there then had to be another (separate, but apparently identical) assessment of seriousness in terms of paragraphs 8 to 18 of the Definitive Guideline. In the present case, the sheriff appears to have carried out only one assessment of seriousness, and in doing so he erred in law.
 The Solicitor General reiterated that the sheriff erred in categorising this as a momentary inattention - the respondent was not looking where he should have looked, on a road where there was a marked cycle lane and good visibility. This was more serious than merely momentary inattention. As is clear from paragraphs 17 and 18 of the Definitive Guideline, cyclists are vulnerable road users and a driver is expected to take extra care when driving near them. Driving into a cycle lane is identified as an example of a factor which should be taken into account when determining the seriousness of an offence. The fact that the victim of a causing death by driving offence was a particularly vulnerable road user is a factor that should be taken into account when determining the seriousness of an offence.
 Although the respondent stated in evidence that there was a bus travelling in the opposite direction, which was the principal focus of his attention, and the police accident reconstruction expert agreed that it was possible that the bus may have obscured the cyclist immediately before the respondent began to turn, it was submitted that if anything this rendered the respondent's culpability greater than if there was no bus - it was obviously incumbent on the respondent to look to his right after the bus had passed the junction and before he commenced his turning manoeuvre. In all these circumstances the seriousness of the offence should properly have been categorised as falling towards the high end of the middle category of the table on page 15 of the Definitive Guideline, overlapping into the first (or most serious) category. This would exclude a non-custodial sentence. The starting point should therefore be category two, and the sheriff erred in adopting a starting point of category three.
 With regard to aggravating factors, the sheriff correctly identified that there was only one such factor relevant in the present case, namely a previous conviction involving bad driving. This could hardly be more serious or more in point. There is no indication in the sheriff's report of what weight he attached to this factor, except the age of the previous conviction. It is the most serious relevant previous conviction that the respondent could have, and it was submitted that public safety should have played a greater part in the sheriff's reasoning. Although it was 27 years since the earlier offence, the respondent only obtained a driving licence again after this offence in 2003, so he had only been driving for about 8 years before the current offence occurred. There is no mention of this in the sheriff's report. Accordingly the sheriff not only erred in his initial assessment of the culpability of the respondent's driving, but he gave insufficient weight to the previous conviction.
 The sheriff took into account two mitigatory factors, namely (a) the action of Mrs Fyfe in not wearing a cycle helmet, and (b) the respondent's remorse. The Solicitor General submitted that the sheriff erred with regard to each of these factors. There were two points to be made about the decision of Mrs Fyfe not to wear a cycle helmet. First, this is not properly a mitigatory factor for the purpose of the Definitive Guideline. It was analogous to the failure by the victim to wear a seatbelt when in a car. Judicial doubts have been expressed as to whether this was a mitigatory factor at all - see R v Powell  EWCA Crim 3265;  2 Cr App R (S) 41. This matter was also considered (albeit before publication of the Definitive Guideline) by this court in Wright v HM Advocate 2007 SCCR 139.
 In any event, no evidence was led before the sheriff as to the consequence of not wearing a cycle helmet, and no submissions were made to him on behalf of either the Crown or the defence in this respect. The sheriff erred in treating this as a matter of judicial knowledge. Reference was made to Walker & Walker, The Law of Evidence in Scotland (3rd ed) at paragraph 11.6.1 where, in discussing what matters fall within judicial knowledge, the authors state that:
"In general they are matters which can be immediately ascertained from sources of indisputable accuracy, or which are so notorious as to be indisputable. If a matter is not immediately notorious or ascertainable the party who seeks to prove the matter should be prepared to lead evidence in direct proof of it or from which the matter will be presumed or inferred."
The Solicitor General referred to three documents lodged on behalf of the Crown for this appeal in this regard. The first was an article entitled "The efficacy of bicycle helmets against brain injury" published in a professional journal entitled "Accident Analysis and Prevention" in 2003; the second was a presentation to the Gloucestershire Accident Action Group on 24 June 2002 by a consultant in cycling skills and safety; and the third was an article entitled "No clear evidence from countries that have enforced the wearing of helmets" written by a senior statistician and published in the British Medical Journal in March 2006. The Solicitor General did not seek to endorse or refute the views expressed in these documents, but submitted that they indicated immediately that this was a matter of dispute, in which different countries and different professional men of skill and expertise held different views. There were considered opinions on each side of this debate; it could not properly be regarded as a matter within judicial knowledge. There was no evidence before the sheriff that Mrs Fyfe's decision not to wear a helmet contributed significantly to her death; the sheriff's views on this matter were mere speculation.
 With regard to remorse, this was expressed at interview in connection with the preparation of the Criminal Justice Social Work Report after trial, approximately 18 months after the offence. It should be borne in mind that the respondent maintained his plea of not guilty and proceeded to trial. The explanation which he gave to the author of the Criminal Justice Social Work Report for this, namely "that he decided to go to trial not to prove that he was innocent but to ensure that the victim's family knew the truth of what had happened" was odd and not credible. There are different levels of remorse; the remorse of the respondent, expressed at the end of the criminal process, should be categorised as being at the lowest end (although the Solicitor General accepted that it is difficult for an appeal court to go behind a trial judge's assessment that remorse was genuine).
 Having regard to each and all of the factors discussed, the Solicitor General submitted that this case met the high test set by HM Advocate v Bell. Any reasonable assessment of the relevant factors, and exclusion of irrelevant factors, would place this case at the high end of category two, overlapping into category one. It followed, on the basis of the Definitive Guideline, that the minimum sentence which the sheriff could properly have imposed was one of 36 weeks imprisonment. Only a custodial sentence was appropriate in this case, particularly having regard to the need to protect the public from the respondent's driving. In addition, such a sentence would give a clear indication of how seriously the court regarded this offence.
 Finally, even if the court were not to be persuaded that the sheriff was unduly lenient in imposing a non-custodial sentence, it was open to the court to look to the period of disqualification as a separate aspect of the sentence, and to conclude that a period of five years disqualification was unduly lenient (HM Advocate v McKay 2011 SLT 250). Having regard to the respondent's previous conviction and to the twice fatal consequences of his driving, the period of five years disqualification was unduly lenient and inadequate to provide sufficient protection to the public. He had been disqualified from driving for ten years following his conviction in 1986; when he resumed driving in 2003 he should have been particularly careful. The only way to ensure the protection of the public, and particularly to ensure the protection of vulnerable road users, would be to impose a lifetime disqualification.
Submissions for the
 Senior counsel began his submissions by suggesting that a lifetime ban from driving was incompetent. In any event, the sheriff was quite correct in the approach which he took to sentencing. The respondent's evidence at trial (which was not contradicted) was that Mrs Fyfe was not visible to the respondent at first because his view was obscured by a bus travelling in the opposite direction from him. After the bus passed the junction, the respondent began his manoeuvre. Too late (and culpably) he saw the cyclist. He attempted to swerve, and clipped the rear wheel of the bicycle. Mrs Fyfe continued for some distance before falling to the ground, causing head injuries which undoubtedly caused her death some two days later. A police officer who attended at the scene gave evidence at the trial and spoke to the obvious upset of the respondent and to the fact that the respondent asked to be kept informed of the progress of the lady. The respondent expressed remorse at the time of the accident, long before his interview with the social worker; he was so distraught by the collision and its consequence that he has not been able to work since. The sheriff was correct to categorise the respondent as being guilty of momentary inattention, the result of which was a low impact, low speed collision with the victim's bicycle. The sheriff was entitled to take the view which he did of the respondent's previous conviction. The respondent did not drive for a further ten years after the end of his earlier disqualification, and he had not come to the court's attention for any road traffic matter in the intervening period until the present tragic incident.
 The author of the Social Work Report had sight of the respondent's prescription for medication for PTSD, and was satisfied that the respondent appeared to suffer from this condition and had lost his job as a result. There were numerous adminicles of evidence from which it could be inferred that the respondent's expressions of remorse were genuine, and the sheriff was entitled to draw the conclusion that he was genuinely remorseful. This court was not in a position to look behind that assessment.
 Mr Kerrigan submitted that the Solicitor General's argument that the sheriff required to look at the culpability of the respondent on two separate occasions in the course of the sentencing exercise was unsound and had no basis.
 This court must look at the sheriff's eventual conclusion and ask whether, in all the circumstances, he exercised his discretion properly and whether he had regard to all the relevant features. It was not appropriate to parse the sheriff's decision too closely. With regard to the absence of a cycle helmet, the sheriff applied simple common sense and he was entitled to do so. His report shows that the sheriff weighed matters up with great care and concern. He gave due weight to each factor, and his decision was one which fell within the range of his judicial discretion. The court should not interfere with his sentence, either as to the Community Payback Order or as to the period of disqualification.
 As the Solicitor General accepted in her submissions to us, the court will not lightly grant an appeal by the Crown against sentence. The test which the Crown must satisfy in order to succeed in an appeal such as this is a high one, and was expressed succinctly by the Lord Justice General giving the Opinion of the Court in HM Advocate v Bell (at page 250) as follows:
"It is clear that a person is not to be subjected to the risk of an increase in sentence just because the Appeal Court considers that it would have passed a more severe sentence than that which was passed at first instance. The sentence must be seen to be unduly lenient. This means that it must fall outside the range of sentences which the judge at first instance, applying his mind to all the relevant factors, could reasonably have considered appropriate. Weight must always be given to the views of the trial judge, especially in a case which has gone to trial and the trial judge has had the advantage of seeing and hearing all the evidence. There may also be cases where, in the particular circumstances, a lenient sentence is entirely appropriate. It is only if it can properly be said to be unduly lenient that the Appeal Court is entitle to interfere with it at the request of the Lord Advocate."
 With that test in mind, we turn first to the Crown's submission in relation to the sheriff's treatment of mitigating factors, and in particular his approach to the fact that Mrs Fyfe was not wearing a cycle helmet.
 In this regard, the sheriff helpfully appended to his report to us a transcript of his recording of his sentencing remarks. From this he made it clear that he was not attributing any blame to Mrs Fyfe. He made the following remarks in the course of sentencing the respondent:
"I also take into account, without criticising in any way Mrs Fyfe (who was not at all to blame for anything) ... I'm bound to take into account the factor that she was not wearing a safety helmet; and that contributed, in my view, significantly to the death."
 We agree with the sheriff's observation that Mrs Fyfe was not at all to blame for anything. However, we have doubts as to whether the fact that a cyclist did not wear a cycle helmet is properly to be regarded as a mitigatory factor in the assessment exercise under the Definitive Guideline. It is at least arguable that paragraph 24 of the Definitive Guideline is directed towards the culpability of the accused's driving (for example, where the victim contributed to the occurrence of a collision to some extent by his/her bad driving), rather than with an element of causation of death. There may be some force in the analogy drawn by the Solicitor General with cases in which the deceased failed to wear a seatbelt. R v Powell was a case of causing death by careless or inconsiderate driving in which the accused caused the death of his friend who was a passenger in the car that the accused was driving. The passenger was boisterous and not wearing a seatbelt. The Court of Appeal was not impressed with the argument that the fact that the deceased was boisterous and not wearing a seatbelt should be regarded as mitigatory factors. At paragraph 16 of its judgment the court observed as follows:
"It is said on his behalf that he was driving in difficult conditions, with a boisterous passenger. If that is so, it cannot, in our judgment, amount to mitigation for his admitted careless driving. Nor does the fact that his passenger was not wearing a seatbelt. If anything, those were surely factors that urged greater caution in a motorist than might normally have been required."
Failure to wear a seatbelt was considered by this court in Wright v HM Advocate, albeit that this pre-dated the Definitive Guideline. In that case the failure was not by a passenger in the accused's car, but by a passenger in a car travelling in the opposite direction. In his report to the Appeal Court the trial judge made the following observation:
"No evidence was placed before me as to what the consequences for the deceased might have been if she had worn a seatbelt, and in these circumstances it appears to me that this involves an element of speculation. In any event, I have doubts as to the relevance of this matter; the jury found the appellant guilty of causing the death of the deceased by dangerous driving, and in the light of that verdict my principal focus when sentencing was on the quality of the appellant's driving and not on speculation as to what might or might not have happened if the deceased had worn a seatbelt."
 On appeal, this court stated (at paragraph ):
"We consider that the trial judge was correct to disregard the factors that the deceased was not wearing a seatbelt at the time of the accident ... In our opinion, the approach the trial judge took ... cannot be criticised."
 However, we do not consider that it is necessary for us to determine this matter in the present case, because we consider that the submissions on behalf of the Crown that the sheriff fell into error in treating this as a matter of judicial knowledge are well-founded. No evidence was led before the sheriff as to the effect of not wearing a cycle helmet, and whether or not this may have caused or contributed to Mrs Fyfe's death. No submissions were made to the sheriff by either party in this regard. It is clear from the material placed before us that there is a degree of controversy as to the efficacy of cycle helmets in preventing death. We consider that the sheriff was wrong to regard this as a matter of judicial knowledge. The view which he reached was based not on evidence but on speculation, and in this respect he fell into error. He should not have treated the fact that Mrs Fyfe was not wearing a cycle helmet at the time of the collision as a mitigatory factor.
 The Solicitor General also criticised the sheriff for his treatment of the respondent's remorse as a mitigatory factor. We do not consider that there is force in this criticism. The sheriff records that there was evidence that the respondent displayed remorse at the time of the accident, and this was reiterated in the course of his evidence at trial and in his remarks to the author of the Criminal Justice Social Work Report. While there is some force in the Solicitor General's observation that the reason given by the respondent to the author of that report for proceeding to trial was strange, it must be remembered that the sheriff had the benefit of seeing and hearing the respondent as he gave evidence in court. He was able to assess his demeanour as a witness. The sheriff was in a much better position than this court to assess whether the respondent's remorse was genuine. Paragraph 28 of the Definitive Guideline states that:
"It is for the court to determine whether an expression of remorse is genuine; where it is, this should be taken into account as personal mitigation."
The sheriff assessed the respondent's remorse as genuine, and there is no material which would justify this court in interfering with that conclusion.
 With regard to the culpability of the respondent's driving, the Solicitor General attacked the sheriff's categorisation of this as momentary inattention. However, we do not consider that there is force in this criticism. It was not disputed on behalf of the respondent that he was culpable in failing to look to his right before he began the manoeuvre of turning to his right. The respondent accepted in evidence that if he had looked right before starting to manoeuvre he would have been alerted to the fact that Mrs Fyfe was on a bicycle crossing the junction, and if he had been aware of this he would not have carried out the manoeuvre. It was also accepted that because of his careless driving the most tragic of consequences resulted. However, in all the circumstances, we cannot disagree with the sheriff's categorisation of this as a momentary inattention, the result of which was a low impact, low speed collision with Mrs Fyfe's cycle. Mrs Fyfe was clearly a vulnerable road user, and the sheriff recognised this. However, the sheriff carried out a careful and detailed assessment of culpability as recommended in the Definitive Guideline, and we can detect no error in the way in which he went about this delicate task.
 We agree with the submission by Mr Kerrigan QC for the respondent that there is no basis for the Crown's submission that the Definitive Guideline requires a sentencer to consider the issue of culpability twice, at separate stages of the assessment exercise. The Crown's submission in this regard appeared to rely on the fact that in the introduction to the Definitive Guideline, at paragraph 3, it is stated that the factor that primarily determines the starting point for sentence is the culpability of the offender, and accordingly the central feature should be an evaluation of the quality of the driving involved and the degree of danger that it foreseeably created, and that the Definitive Guideline goes on, at paragraphs 8 to 18, to list five factors that may be regarded as determinants of offence seriousness. However, we consider that on a proper construction of the Definitive Guideline as a whole, the introductory paragraphs form an "executive summary" and that the subsequent paragraphs are a more detailed exposition of the principles set out in the introduction. We think there is nothing in the Definitive Guideline, nor in logic or common sense, which would require a sentencer to consider and assess culpability (applying apparently the same criteria) at two separate stages of the process.
 The sheriff applied his mind carefully to the five criteria set out at paragraphs 8 to 18 of the Definitive Guideline, and correctly identified that the only one which was relevant was that Mrs Fyfe was a cyclist and therefore a vulnerable road user. We can detect no error in the reasoning which led him to the conclusion that, as a first step, the respondent's driving should be placed in the third, least serious, level of gravity.
 The sheriff then went on to consider aggravating factors, and the Crown accepts that he was correct in identifying only one such factor, namely the previous conviction in 1986 for causing death by reckless driving. This was of course a serious conviction, and a relevant factor in the sentencing exercise. The Solicitor General submitted that the sheriff gave insufficient weight to this. However, the sheriff sets out in some detail in his report to us his approach to the previous conviction. This approach did not depend only on the fact that the previous conviction was some 27 years ago, but also took account of the quality of the respondent's driving. The sheriff stated that had the quality of the respondent's driving been at the more serious end of the range of carelessness, he would have been entitled to infer that the respondent had not learnt his lesson from the prior conviction, imprisonment and disqualification, but he was not able to do so. He was not prepared to attach such weight to the prior conviction that imprisonment would have become inevitable in accordance with the sentencing guidelines.
 It is perhaps easy to take a superficial view that by his bad driving the respondent has caused the death of two people in two road accidents over 27 years, and that this required to be marked with a sentence of imprisonment. However, the sheriff has carried out the delicate and detailed sentencing exercise recommended by the Definitive Guideline with considerable care, and has given full reasons for the conclusion which he reached. This court must give weight to his views, particularly given that this is a case which has gone to trial and the sheriff has had the advantage of seeing and hearing all the evidence. Despite the sheriff's error in treating the fact that Mrs Fyfe was not wearing a cycle helmet as a mitigatory factor, we are unable to say that the sentence of a Community Payback Order with the maximum number of unpaid hours was unduly lenient. It did not fall outside the range of sentences which the sheriff, applying his mind to all the relevant factors, could reasonably have considered appropriate. In particular, we cannot say that, in all the circumstances of this case, the sheriff could only have reasonably considered a sentence of imprisonment to be appropriate.
 Each case of this nature turns very much on its own facts and circumstances, and little is to be gained by a comparison with other cases. However, we note that in the only other Scottish case to which we were referred relating to section 2B of the Road Traffic Act 1988 in which the Crown argued that a sentence was unduly lenient, namely HM Advocate v McKay 2011 SLT 250, in which the driver of a motor car drove at excessive speed, failed to negotiate a double bend, crossed onto the wrong side of the road and killed a cyclist, the court could not describe the sheriff's decision to select a Community Service Order of 300 hours (prior to discount) as meeting the test for a Crown Appeal against sentence of being unduly lenient. The court in that case did not consider that the sheriff's decision to make a Community Service Order could be said to be so outwith the range of disposals available to him as to be unduly lenient. We have reached the same conclusion in the particular facts and circumstances of this case.
 Finally, we deal with the length of disqualification imposed. It would be competent for us, if we saw fit, to quash the period of disqualification imposed by the sheriff and to impose a longer period. That was done in HM Advocate v McKay; in that case, involving the loss of control of a vehicle being driven at excessive speed and crossing into the opposite carriageway, the court increased the period of disqualification from the statutory minimum of one year to four years. It should be borne in mind that in the present case the sheriff disqualified the respondent from driving for five years, and until he has passed the extended test of competence to drive. Notwithstanding the previous conviction in 1986, we are unable to agree with the Solicitor General's submission that this is inadequate to provide sufficient protection to the public. This is a disqualification for a significant number of years, and even after those years have expired, the respondent will not be able to drive (if indeed he wishes to do so) until he has passed the extended test of competence. Again, we cannot say that this aspect of the sheriff's disposal was so outwith the range available to him as to be unduly lenient.
 For these reasons this appeal must be refused.