Pursuers and reclaimers: Howie QC, O'Brien; MacRoberts LLP

Defenders and respondents: The Dean of Faculty, Springham; HBM Sayers

14 March 2013

Introduction

[1] On 11 May 2004, there was an explosion in the defenders' plastics factory. People were killed and injured. The pursuers' nearby shop suffered extensive damage. Subsequent investigations revealed that an underground pipe feeding liquefied petroleum gas (LPG) to an oven in the factory had become corroded and cracked, and had leaked LPG into the basement. The explosion was caused by the ignition of that explosive atmosphere.

[2] On 17 August 2007 in the High Court of Justiciary in Glasgow, the first and second defenders pled guilty to charges under section 33(1)(a) of the Health and Safety at Work etc Act 1974. Those charges alleged inter alia failure to make a suitable and sufficient assessment of the risks to the health and safety of employees by failing to identify that the pipework conveying LPG to the premises presented a potential hazard and risk; failure to appoint competent persons to assist in carrying out such risk assessments; failure to have a proper system of inspection and maintenance of the LPG pipework; and failure to ensure so far as reasonably practicable that the pipework was maintained in a condition that was safe and without risk to employees.

[3] The health and safety prosecution was followed by a public inquiry into the explosion. As is recorded at paragraph 6.94 of Johnston, Prescription and Limitation (2nd ed):

" ... it took a lengthy public inquiry to establish the cause of the explosion. [The inquiry] reported only in July 2009 ..."

[4] On 13 August 2009, the pursuers served a summons on the defenders. In that summons, reference was made to the pleas of guilty. In Article 5 of Condescendence, the pursuers averred that the explosion was caused by the fault and negligence of the defenders. They averred that the defenders failed to have in place a system of periodic inspections with a view to identifying any corrosion in the pipe at an early stage, and preventing any corrosion from developing to a point where it posed a danger of gas escaping. In Article 6 they averred a breach of the Pressure Systems Safety Regulations 2000. In Article 7 they averred that the escape of gas from the LPG pipe and the resultant explosion constituted a nuisance, under reference to negligence, breach of the 2000 Regulations, breach of section 3(1) of the 1974 Act, breach of regulation 5 of the Provision and Use of Work Equipment Regulations 1998, and breach of their duties under regulation 3 of the Management of Health and Safety at Work Regulations 1999. In Article 8 they described their losses, resulting in the damages claimed of £1.45 million.

[5] Defences lodged on behalf of the defenders contained an admission of liability, but also a plea-in-law to the effect that any obligation to make reparation had prescribed by reason of the quinquennial prescription as follows:

"3. Any obligation incumbent on the defenders, or any of them, arising out of liability to make reparation to the pursuer having been extinguished by the operation of the quinquennial prescription under section 6 of the Prescription and Limitation (Scotland) Act 1973, the action should be dismissed."

[6] The pursuers responded with the following plea-in-law:

"3. The commencement of the prescriptive period having been deferred until after five years before the commencement of the action as the pursuer would not in the exercise of reasonable diligence have earlier discovered that it had suffered loss as a result of [an] act, neglect or default, the defenders' pleas anent prescription should be repelled."

The legislation

[7] Sections 6, 11, and Schedule 1 of the Prescription and Limitation (Scotland) Act 1973 provide inter alia as follows:

"6. Extinction of obligations by prescriptive periods of five years

(1) If, after the appropriate date, an obligation to which this section applies has subsisted for a continuous period of five years -

(a) without any relevant claim having been made in relation to the obligation, and

(b) without the subsistence of the obligation having been relevantly acknowledged,

then as from the expiration of that period the obligation shall be extinguished ...

(3) In subsection (1) above the reference to the appropriate date, in relation to an obligation of any kind specified in Schedule 2 to this Act is a reference to the date specified in that Schedule in relation to obligations of that kind, and in relation to an obligation of any other kind is a reference to the date when the obligation became enforceable...

11. Obligations to make reparation

(1) Subject to subsections (3) and (3) below; any obligation (whether arising from any enactment, or from any rule of law or from, or by reason of any breach of, a contract or promise) to make reparation for loss, injury or damage caused by an act, neglect or default shall be regarded for the purposes of section 6 of this Act as having become enforceable on the date when the loss, injury or damage occurred...

(3) In relation to a case where on the date referred to in subjection (1) above (or, as the case may be, that subjection as modified by subsection (2) above) the creditor was not aware, and could not with reasonable diligence have been aware, that loss, injury or damage caused as aforesaid had occurred, the said subsection (1) shall have effect as if for the reference therein to that date there were substituted a reference to the date when the creditor first became, or could with reasonable diligence have become, so aware...

SCHEDULE 1

OBLIGATIONS AFFECTED BY PRESCRIPTIVE PERIODS OF FIVE YEARS UNDER SECTION 6

1. Subject to paragraph 2 below, section 6 of this Act applies -

... (d) to any obligation arising from liability (whether arising from any enactment or from any rule of law) to make reparation;".

The Lord Ordinary's decision
[8] A debate on the issue of prescription took place before Lord Woolman. On 9 March 2012, the Lord Ordinary sustained the defenders' plea of prescription, repelled the pursuers' pleas-in-law, and dismissed the action. His reasons are contained in paragraphs [33] et seq of his opinion. The pursuers reclaimed.

Submissions for the pursuers and reclaimers

[9] Senior counsel invited the court to allow the reclaiming motion, recall the Lord Ordinary's interlocutor of 9 March 2012, and remit the action back to the Outer House for a proof before answer on the question of prescription.

[10] The Lord Ordinary had dismissed the action on the ground that the pursuers could have proceeded on the basis of res ipsa loquitur, and thus that the prescriptive period started running on the day of the explosion. However the pursuers' contention was that it was necessary for them to make some investigation (in the exercise of reasonable diligence) into the cause of the explosion. The pursuers had been unaware that they had suffered loss caused by an act, neglect or default until a point in time which was well within the five year period. There was no presumption that a loss such as that suffered by the pursuers was caused by negligence. It was quite possible that there was no fault. It was only once the pursuers had carried out investigations and had ascertained the cause, or alternatively that it was not known what had caused the explosion (when res ipsa loquitur could be resorted to) that the prescriptive period began to run.

[11] Counsel referred to sections 6 and 11 of the 1973 Act. The pursuers' position was that, in terms of section 11(3), the prescriptive period began to run only when the pursuers became aware, or could with reasonable diligence have become aware, that the "loss, injury or damage caused as aforesaid [ie by an act, neglect or default]" had occurred. In the present case, the pursuers were not actually aware of those facts until a date within the five year period. It was accepted that the prescriptive period began to run once the pursuers knew that the loss had been caused by fault and negligence on the part of "someone". It was not necessary that the pursuers knew who that someone was (Greater Glasgow Health Board v Baxter Clark and Paul 1990 SC 237, pages 249 to 250, 252; Glasper v Rodger 1996 SLT 44, pages 47 to 48).

[12] Once the pursuers were aware of their loss, they had to take steps to find out what had caused that loss, and to find out whether there was some act or omission for which someone was liable to make reparation. Res ipsa loquitur could be relied upon only when steps had been taken to investigate the event, and a blank had been drawn. Each case depended on its particular facts. It might be immediately evident that one would never find the answer; or it could be a case where steps had to be taken to investigate, resulting in the discovery of negligence, or the discovery that there had been no negligence, or finally that an answer could not be found. In that latter situation, the pursuers could rely upon res ipsa loquitur, and the onus of establishing what had happened then passed to the defenders.

[13] The defenders relied heavily upon Lord Emslie's decision in AMN Group Ltd v Gilcomston North Ltd 2008 SLT 835, paragraph [58]. But that case did not vouch the proposition that res ipsa loquitur could form the ab initio basis of every case. On the contrary, the maxim could be relied upon only in certain circumstances (Scott v London & St Katherine's Docks Co 1865 3 H & C 596, at pages 666 to 667; Ballard v North British Railway Co 1923 SC (HL) 43, at pages 53 to 56). It was only when the pursuer could say "it is incapable of explanation by me as the pursuer" that the onus transferred to the defender (O'Hara v Central SMT 1941 SC 363 at page 379; McQueen v Glasgow Garden Festival (1988) Ltd 1995 SLT 211 at page 214). Res ipsa loquitur was a concession to the pursuer, altering the normal rule that the onus of proof lay on the pursuer. The maxim could be relied upon only where, with the resources available to the pursuer, the pursuer was unable to prove what had caused the incident and whether it was due to negligence. Res ipsa loquitur could not be relied upon where the facts were capable of ascertainment (Bolton v Stone [1951] AC 850 at pages 859-860; O'Hara v Central SMT cit sup at page 388; Walker's Delict (2nd ed) pages 397, 399; Green's Delict Looseleaf paragraph 5.177). Thus in circumstances where the facts were susceptible of discovery, it was for the pursuer to make investigations, set out his case, and prove the acts or omissions which were negligent. The pursuer could not sit back, rely on res ipsa loquitur, and throw the burden of proof onto the defender.

[14] Explosions could occur without negligence. A failure in a gas pipe might arise from a design error unknown at the time of installation, but now appreciated. Section 11(3) allowed a pursuer a period of time to act with reasonable diligence to try to discover what had occurred. Res ipsa loquitur was a "last chance" card.

[15] In the present case, it was ultimately ascertained that the pursuers' loss and damage was caused by an act, neglect or default on the part of the defenders. There had been an exhaustive inquiry (an FAI) during which the Crown uncovered the defenders' negligence. Once that was ascertained, res ipsa loquitur was no longer available.

[16] Senior counsel then addressed particular passages in the Lord Ordinary's opinion. In relation to paragraph [11], a claim was hardly "stale" when it was the subject of intense scrutiny in an FAI. The balance referred to in paragraph [15] was not destroyed by the pursuers' argument. Certainty and finality were achieved by the twenty year prescription. The case of Pelagic Freezing (Scotland) Limited v Lovie Construction Limited [2010] CSOH 145, referred to in paragraph [23], did not materially affect the debate. The proposition in paragraph [34] was criticised. The question whether there had been negligence was material, and the pursuer had to investigate the facts. In the present case, the facts were ascertainable, and res ipsa loquitur was simply not applicable (Barkway v South Wales Transport Co Ltd [1950] 1 All ER 392, Lord Porter at pages 394 to 396, 399 to 400).

[17] In paragraph [37], the Lord Ordinary stated "Buildings do not explode spontaneously", and then based his reasoning on that proposition. In so doing, he failed to take into account the fact that buildings could explode without negligence. In relation to paragraph [42], it was for the pursuer and his experts to investigate the cause of the loss and damage. Certain ethical standards were expected from lawyers.

[18] The leading authority on nuisance (RHM Bakeries (Scotland) Ltd v Strathclyde RC 1985 SC (HL) 17) was referred to in paragraph [43] of the Lord Ordinary's opinion. That decision did not assist, as res ipsa loquitur was not in fact available in the present case, and in any event nuisance was based on culpa or fault (Argyll & Clyde Health Board v Strathclyde RC 1988 SLT 381). Accordingly the pursuers' submissions (about their having to investigate whether an act, neglect or default had caused the loss) were not affected by whether or not nuisance was pled.

[19] In paragraph [45] the Lord Ordinary stated that the explosion was not "latent damage" (the classic focus of section 11(3)): the explosion was "instantly discoverable". But that was not the point. The question in the present case was not "Did the pursuers realise that they had suffered damage?" Clearly, they did. The question was whether the pursuers knew that the damage had been "caused as aforesaid", in other words, that it had been caused by an act, neglect or default (section 11(3)). As for paragraph [46], if one could not resort to res ipsa loquitur, that paragraph had little relevance.

[20] The Lord Ordinary referred in paragraph [47] to "nice questions" raised by inquiring whether the pursuers had used "reasonable diligence" when investigating the cause of the damage. But Parliament had enacted the statute, and the statute had to be applied. Thus there would indeed be cases where the court would have to decide what amounted to reasonable diligence (Glasper v Rodger 1996 SLT 44; AMN Group Ltd v Gilcomston North Limited 2008 SLT 835, paragraphs 52 to 57). The whole issue was fact-sensitive.

[21] The Lord Ordinary had therefore erred in dismissing the action. The correct approach was not to plead res ipsa loquitur until the pursuers' investigations had drawn a blank. It was not appropriate to raise an action immediately, based on res ipsa loquitur. To do so was inconsistent with Glasper, and also with current practice in reparation cases. The reclaiming motion should be allowed, the Lord Ordinary's interlocutor of 9 March 2012 should be recalled, and the case remitted to the Lord Ordinary for a proof before answer on the question of prescription and section 11(3).

Submissions for the defenders and respondents

[22] For the defenders and respondents, the Dean of Faculty invited the court to adhere to the interlocutor of the Lord Ordinary, sustaining the defenders' third plea-in-law and dismissing the action.

[23] No distinction was drawn between negligence, breach of statutory duty, or nuisance. It was accepted that these claims stood or fell together. The maxim res ipsa loquitur was simply a useful shorthand applied in an evidential context. An event could speak for itself. For example, in normal course a bus driven with reasonable care did not swerve. Accordingly it would be sufficient to say "The bus swerved and I was injured". But the driver (the defender) might respond with an explanation as to why he swerved, which did not demonstrate any lack of care on his part. At that stage, the event ceased to speak for itself.

[24] If a lorry crashed into a house, it was not for the householder to have the driver's medical condition investigated. Lorries driven with reasonable care did not collide with houses: the event spoke for itself. If the defenders could then demonstrate that the driver had suffered an unexpected heart attack, the event ceased to speak for itself. However the householder might respond with an accusation that the defenders had engaged a driver with a known risk of having heart attacks. So the case began with res ipsa loquitur, and then developed into a situation where res ipsa loquitur ceased to be applicable.

[25] The pursuers claimed that they could not plead res ipsa loquitur until they had made an investigation into the case. That was not correct. The pursuers' proposition confused pleading a case with proving a case. If a pursuer had a prima facie stateable ground of action, he could plead it. For example, in Mrs O'Hara's case, she could aver simply that "The bus swerved". If the defenders did not respond with an explanation, and the pursuer led evidence of the swerve, the court was entitled to find the pursuer's case made out. If, on the other hand, the defenders pled an explanation which was exculpatory, the court would allow proof of that exculpatory explanation. If the defenders failed to prove the explanation, the event would still speak for itself. Thus res ipsa loquitur was simply an evidential mechanism. The real issue in O'Hara had been whether there was sufficient corroboration of the driver's exculpatory explanation (in an era when corroboration was still required in civil cases). It was important not to confuse pleading a case with the ultimate proof of a case.

[26] Sections 6 and 11 of the 1973 Act had to be read together. The legislation was designed to give a party five years to decide whether or not to raise an action. There were certain exceptions to the five-year timebar (for example, fraud and error induced). But the pursuers' argument suggested that every case was an exception, as the date of the event was not the terminus a quo but merely the starting-point for inquiry. That could not be correct, as it was the policy of Parliament that any obligation to make reparation should be extinguished after a period of five years after the date on which the obligation became enforceable - i.e. the concurrence of damnum and injuria (Dunlop v McGowans 1980 SC (HL) 73). Five years was more than sufficient time for a pursuer to raise an action. If Parliament had intended section 11(3) to be read as the pursuers suggested, it would have been phrased differently.

[27] Counsel for the pursuers maintained that the pursuers could not raise an action until they had fully investigated all the circumstances of the explosion in order to determine the cause, or to reach a view that the cause was unascertainable. But that would result in uncertain and subjective measurements. For example, was it unascertainable to the pursuer's expert (although readily ascertainable to another expert). In normal course, a building did not explode. The event spoke for itself. But the defenders might be able to prove that a third party planted a bomb. Then the pursuer might aver that the defenders had failed to keep their premises reasonably secure. Thus the action would initially rely upon res ipsa loquitur, but would develop as parties pled their cases (cf dicta of Lord Fraser of Tullybelton at page 45 of RHM Bakeries v Strathclyde RC 1985 SC (HL) 17; Ballard v North British Railway 1923 SC (HL) 43, Lord Dunedin at page 54). Section 11(3) set an objective test, not a subjective one. When the explosion occurred, the pursuers knew that very day that they had suffered damage. They also knew (whether by actual or imputed knowledge) that the damage had been caused by an act, neglect or default of the defenders, or at least, of someone other than the pursuers. Thus the pursuers' counsel could have pled a prima facie case on the day of the explosion. Whether the case would in fact be made out at the end of the day was neither here nor there.

[28] It was accepted that there were some cases in which the event itself was neutral and there was no res ipsa loquitur. But the present case was not such a one. There was sufficient for the pursuers to raise an action. The summons could simply aver the explosion, the loss and damage caused by the explosion, and the fact that such an event would not occur in normal course if reasonable care were taken. It would then be for the defenders to offer an explanation consistent with lack of fault on their part (Lord Dunedin at page 54 of Ballard cit sup; Lord Fraser of Tullybelton at page 45 of RHM Bakeries cit sup). Averments of res ipsa loquitur could be made along with averments of failure to maintain the gas system. If the pursuers failed to prove the latter averments, they could rely on the former.

Discussion
[29] Section 11 of the Prescription and Limitation (Scotland) Act 1973 provides inter alia:

"11. - Obligations to make reparation

(1) Subject to subsections (2) and (3) below; any obligation (whether arising from any enactment, or from any rule of law or from, or by reason of any breach of, a contract or promise) to make reparation for loss, injury or damage caused by an act, neglect or default shall be regarded for the purposes of section 6 of this Act as having become enforceable on the date when the loss, injury or damage occurred ...

(3) In relation to a case where on the date referred to in subsection (1) above ... the creditor was not aware, and could not with reasonable diligence have been aware, that loss injury or damage caused as aforesaid had occurred, the said subsection (1) shall have effect as if for the reference therein to that date there were substituted a reference to the date when the creditor first became, or could with reasonable diligence have become, so aware."

Section 11(3) might prima facie be thought to refer solely to latent damage, where a pursuer was unaware that he had suffered any loss or damage. Decisions involving latent damage include Renfrew Golf Club v Ravenstone Securities Ltd 1984 SC 22 (an underlying defect in a newly constructed golf course); Scott Lithgow Ltd v Secretary of State for Defence 1989 SC (HL) 9 (defective submarine cables); and Sinclair v MacDougall Estates Ltd 1994 SLT 76 (building defects). A construction of section 11(3) restricted solely to "latent damage" would not entitle the pursuers in the present case to postpone the start of the prescriptive period, as the explosion on 11 May 2004, and the ensuing damage, were clear and obvious to all. The quinquennium would begin to run, allowing the pursuers five years within which to ascertain the cause of the explosion, whether it had been caused by negligence, and if so, who was responsible for that negligence.

[30] However it has been authoritatively decided that section 11(3) applies not only in cases of latent damage, but also in cases where a pursuer is aware of his loss and damage, but does not know whether that loss and damage was caused by negligence. In Greater Glasgow Health Board v Baxter Clark & Paul 1990 SC 237, 1992 SLT 35, at page 251 et seq (page 40D et seq in 1992 SLT), Lord Clyde reasoned as follows:

"The question is one of the interpretation of section 11(3) ... In my view ... the subsection looks for an awareness not only of the fact of loss having occurred, but the fact that it is a loss caused by negligence ... I do consider that the ordinary and natural meaning of the phrase ["caused as aforesaid"] involves an inclusion of the ingredient of causation by fault. The construction advocated by the defenders does not seem to me to give sufficient recognition to the presence of the critical three words. Indeed, if Parliament had intended what the defenders submit is the proper construction, the words could have been altogether omitted. Counsel for the defenders argued that it was necessary to refer to the fact that the loss was loss resulting from an act, neglect or default because it was with that that the section was concerned. As senior counsel for the defenders put it, the critical phrase was inserted to draw attention back to section 11(1) to show the kind of loss of which the creditor has to be aware without making awareness of the fact of causation an essential for the prescriptive period to start running. But the whole section is concerned with claims for reparation which involve damnum caused by injuria and it does not seem to me that the critical words could have been added simply as a reminder of that. They must be there for some purpose and they must be given some meaning. In accordance with the ordinary use of the language which is used, awareness of loss having occurred is not enough. What the subsection requires is awareness of loss caused by negligence having occurred.

Furthermore as senior counsel for the pursuers submitted, the logic of the scheme points to a requirement of knowledge that the right of action exists before the obligation is deemed to be enforceable and it would be illogical to omit one of the essential components of the right of action, namely the causation of the loss by fault. Even more compelling to my mind was his further submission that if it is only knowledge of the fact of loss, injury or damage having occurred which is intended, it is difficult to give much content to the reference to reasonable diligence. The more likely context for reasonable diligence is in the steps that may be taken after loss has been sustained to discover the cause of it ..."

Lord Clyde's approach to section 11(3) was approved by the Inner House in Glasper v Rodger 1996 SLT 44, where Lord President Hope observed at page 47 F-G:

"In our opinion the lack of awareness which requires to be established for the purposes of section 11(3) of the 1973 Act is a lack of awareness that a loss has occurred caused by an act, neglect or default which gives rise to an obligation to make reparation for it. We agree with Lord Clyde's observation in Greater Glasgow Health Board v Baxter Clark & Paul 1992 SLT at page 40D that the subsection looks for an awareness not only of the fact of loss having occurred, but of the fact that it is a loss caused by negligence ..."

Thus section 11(3) can be relied upon to defer the start of the five-year prescriptive period to the date when a pursuer first becomes aware that the loss and damage which he has suffered was caused by negligence. As summarised in Johnston, Prescription and Limitation (2^nd ed), paragraph 6.95:

"The courts in Scotland have therefore adopted a consistent approach to the meaning of section 11(3), in treating it as postponing the start of the prescriptive period until the creditor is aware both that he has sustained loss and that it was caused by an act, neglect or default, while taking no account of the fact that the pursuer does not know the identity of the defender ..."

[31] In the present case, one of the defenders' contentions is that the pursuers, on 11 May 2004, were not only immediately aware of their loss and damage as a result of the explosion but were also immediately aware (or could work on the assumption) that the explosion was caused by negligence. We do not agree. While an explosion in a building is a rare occurrence, and while, as the Lord Ordinary correctly observes at paragraph [37] of his opinion, it provides a good basis for a writ averring res ipsa loquitur (about which we say more below), the fact that there has been an explosion in a building does not, in our view, inevitably mean that it must have been caused by negligence. It is unnecessary for present purposes to list examples of non-negligent causes of explosions. However two were discussed during the debate. First, there may have been a deliberate act by a third party over whom the owners and occupiers had no control. Secondly, a previously unknown design fault in an underground pipe may have caused the explosion. In our view it is necessary in the present debate to keep the possibility of non-negligent causes in mind, and the fact that it may not be possible confidently to exclude non-negligent causes in every case without some investigation.

[32] Thus while we accept that on 11 May 2004 the pursuers undoubtedly knew that they had suffered loss and damage as a result of an explosion in the defenders' premises, they did not at that stage know that the explosion had been caused by negligence.

[33] There is then the question of the import and effect of the legal maxim res ipsa loquitur. It was submitted on behalf of the defenders not only that it must have been obvious on 11 May 2004 that the explosion had been caused by negligence, but that, in any event, a relevant summons could have been drafted on that very day, relying upon the maxim res ipsa loquitur. All the requisite elements were present: the building in which the explosion occurred was in the sole control of the defenders; what occurred was something which did not normally occur if all due care was taken; and no explanation was forthcoming from the defenders consistent with lack of fault on their part. Our response to that argument is as follows.

[34] In our opinion, the maxim res ipsa loquitur is an evidential rule which makes a concession in certain cases where an event appears, prima facie, to be attributable to negligence (the event "speaks for itself"), but a pursuer simply cannot find out precisely what has caused his loss and damage: cf Lord Normand in Barkway v South Wales Transport Co Ltd [1950] 1 All ER 392 at page 399H:

"The maxim is no more than a rule of evidence affecting onus. It is based on commonsense, and its purpose is to enable justice to be done when the facts bearing on causation and on the care exercised by the defendant are at the outset unknown to the plaintiff and are or ought to be within the knowledge of the defendant."

[35] Lord Fraser's observations at page 45 of RHM Bakeries v Strathclyde RC 1985 SC (HL) 17 are to the same effect:

" ...the view that I have just expressed does not by any means imply that, in a case such as this, a pursuer cannot succeed unless he avers the precise nature of the fault committed by the defender which caused the accident. It would be quite unreasonable to place such a burden on a pursuer, who in many cases will have no knowledge, and no means of obtaining knowledge, of the defender's fault. As a general rule it would, in my opinion, be relevant for a pursuer to make averments to the effect that his property has been damaged by a flood caused by an event on the defender's land, such as the collapse of [a] sewer which it was the defender's duty to maintain, that properly maintained sewers do not collapse, and that the collapse is evidence that the defender had failed in his duty to maintain the sewer. The onus will then be on the defender to explain the event in some way consistent with absence of fault on his part ..."

[36] The limitations of the maxim have been emphasised in the authorities. Thus in Ballard v North British Railway Co 1923 SC (HL) 43, Lord Dunedin and Lord Shaw emphasised at pages 54 and 56 that the event does not necessarily speak for itself in every case. Further as was pointed out by Lord Normand at page 399 of Barkway v South Wales Transport cit sup:

" ... if the cause of the accident is proved, the maxim res ipsa loquitur is of little moment ..."

Similarly Lord Porter observed at page 859 of Bolton v Stone [1951] AC 850:

" ... Where the circumstances giving rise to the cause of the accident are unknown, [res ipsa loquitur] may be of great assistance, but where, as in the present case, all the facts are known, it cannot have any application. It is known exactly how the accident happened and it is unnecessary to ask whether this accident would have happened had there been no negligence; the only question is, do the facts or omissions which are known and which led up to the injury amount to negligence ..."

[37] In effect, therefore, a summons based on res ipsa loquitur is a judicial declaration by the pursuer that he does not know what caused the event resulting in his loss and damage, and/or whether any ascertainable cause involved negligence. But because the event speaks for itself, he is placing the burden of ascertaining how and why the damaging event occurred onto those who had sole control of the premises where the event occurred (Scott v The London and St Katherine Docks Company (1865) 3 H & C 596; O'Hara v Central SMT Co Ltd 1941 SC 363 at pages 379, 388; Bolton v Stone [1951] AC 850 at pages 859-860; Walker Delict (2^nd ed) page 399; Green's Delict Looseleaf paragraph 5.177). As the Dean of Faculty submitted (correctly in our view), there might then follow a dialogue between pursuer and defender within the court process. The defender might, in his defences, give an explanation apparently consistent with lack of negligence on his part: for example, an intruder with a bomb (cf observations in Ballard v North British Railway 1923 SC (HL) 43, pages 48 and 54; O'Hara v Central SMT Co Ltd cit sup at page 379; Walker Delict (2^nd ed) page 397). The pursuer might respond with fresh averments of negligence (lack of security in the premises). It might well be that, in the course of adjustment of the pleadings, the pursuer would learn for the first time what was said to have caused the event in question. But none of this would detract from the fact that the pursuer, by raising the action based solely on res ipsa loquitur, was at the outset stating to the court "Doing the best I can, I am unable to discover how or why this accident occurred" and therefore (a fortiori) "Despite my best efforts, I am not in a position to prove negligence, but I wish, in the circumstances of this particular case, to take advantage of the recognised maxim res ipsa loquitur such that, if the defender cannot give the court an explanation consistent with lack of negligence on his part, I should in law be found entitled to damages". In our view therefore, the raising of an action based on res ipsa loquitur is the antithesis of "awareness not only of the fact of loss having occurred, but of the fact that it is a loss caused by negligence" (Lord Hope in Glasper v Rodger cit sup at page 47F). Accordingly a pursuer in such a summons would by definition qualify in terms of section 11(3) of the 1973 Act.

[38] In the present case, the pursuers aver that, as at 11 May 2004, they did not know what had caused the explosion, and a fortiori they did not know whether or not it had been caused by negligence. They aver that there was continuing doubt and debate over the cause. For example, in Article 9 of Condescendence, they aver:

" ... The area surrounding the defender's premises, including the pursuer's property, was sealed off by the police after the explosion. It remained closed for several months afterwards. As hereinbefore condescended upon, the pursuer was not permitted to return to its own property until June 2004. The stock in the pursuer's premises had been contaminated by dust, and there was a risk of asbestos contamination. The issue of stock disposal was resolved in late 2005, and work began on reopening the premises for trading early in 2006. They eventually reopened in October 2006. On around 21 June 2004, the defenders petitioned this court for judicial review of inter alia the procurator fiscal's decision to refuse to allow them access to their own property for purposes of investigation. In Statement 4 of that petition, it was averred that the present defenders required 'to form a prima facie view on the cause or causes of the said explosion and on their responsibility, if any, therefor'. It was averred that, to that end, the present defenders required to arrange an inspection of the site by an expert witness. The hearing on that petition did not conclude until December 2004 and the decision of the court refusing the petition was not issued until 11 March 2005. The pursuer at no time prior to the date five years before the raising of the present proceedings had any opportunity or authority to investigate the defenders' premises or the circumstances of the explosion at those premises on 11 May 2004. In the circumstances, the pursuer was unable to carry out any meaningful investigation into the cause of the explosion. To ascertain whether or not the loss sustained by the pursuer had been caused by an act, neglect or default for which the pursuer would have been able to sue, it was necessary that the premises of the defender be inspected by expert witnesses skilled in the examination and analysis of fire-damaged property, and for such experts to form a conclusion (if they could) as to the cause of the explosion at those premises and thereafter, for those experts to report on those conclusions to the pursuer and his legal advisers in order that the latter might, if that step were found to be warranted on that expert evidence, take proceedings. In the exercise of reasonable diligence, it would have taken the pursuer until after 13^th August 2004 (being the date five years before the service of the summons in this action) to discover whether his loss was so caused. The defender's premises were not released from Crown Office control until 12^th July 2004. It is unlikely that, having ascertained that, such release having occurred, those premises could be inspected by experts retained on the pursuer's behalf, such experts would have obtained permission to carry out the requisite examination of the premises, carried out that examination, formed a view satisfactory to them on the cause of the explosion and reported thereon to the pursuer and its advisers prior to 17^th [sic] August 2004 had they exercised no more than a degree of diligence which would have been accounted reasonable. The period between mid-July and mid-August 2004 fell in the summer holiday period. The cause of the explosion was not readily discovered. Speculation about numerous possible causes of the explosion continued for a substantial period after 11 May 2004. In late 2005 the media were still reporting that the cause of the accident had not been established. In October that year, it was being reported in the newspapers that the exact cause of the explosion 'had not yet been established', and that the Lord Advocate was seeking clarification of some technical information about the case in order to decide on further procedure. Crown Office carried out an investigation and in February 2006 announced its intention to bring criminal proceedings against inter alios the first and second defenders. On 1 October 2007 the Lord Advocate announced that a public inquiry would be held into the explosion. Its remit included inquiring 'into the circumstances leading up to the incident on 11 May 2004'. Until at least that date, the pursuer did not know, and could not have known with reasonable diligence, that its loss and damage had been caused by any act, neglect or default on the part of anyone. In those circumstances, the pursuer having been unaware of the fact that its loss had been caused by an act, neglect or default until after 13^th August 2004, the commencement of the prescriptive period would be deferred under s.11(3) of the Prescription and Limitation (Scotland) Act 1973 until after that date as the taking of steps to discover the said fact would not have served to certiorate the pursuer of that fact until after said date had those steps been pursued with reasonable diligence. With reference to the defenders' averments, admitted that proceedings were raised on 13 August 2009. Admitted that the pursuer was aware as at 11 May 2004 that it had suffered loss and damage. Not known and not admitted what claims had been received by the defenders at the time of presentation of the petition. Quoad ultra the defenders' averments are denied except insofar as coinciding herewith."

[39] On the basis of those averments, we consider that the pursuers are entitled to a proof before answer on the question whether their claim has been extinguished by the quinquennial prescription. We note that on 17 August 2007 the defenders pled guilty to certain health and safety charges. It seems to us that the start of the quinquennium could not be later than that date, but may well be earlier. The pursuers' averments in Article 9 of Condescendence suggest that they could not and did not become aware of negligence on the part of the defenders prior to 13 August 2004. If they prove that, then on the basis of Greater Glasgow Health Board v Baxter Clark & Paul cit sup, and Glasper v Rodger cit sup, it seems to us that the court would find that the defenders' obligation to make reparation to the pursuers for the loss and damage caused by the explosion has not been extinguished by the quinquennial prescription, because of the operation of section 11(3) of the 1973 Act. But the resolution of that particular issue would ultimately be one for the Lord Ordinary who hears the evidence and submissions at the proof before answer. It would be for the Lord Ordinary to assess:

" ... whether the pursuers were by the critical [date] aware, or could with reasonable diligence have become aware, that relevant loss and damage known to them was actionable, in the sense that a stateable prima facie claim in negligence could properly be advanced against someone. Certainty or even probability of success in any such claim would not, I think, be required ..."

(AMN Group Ltd v Gilcomston North Ltd 2008 SLT 835, paragraph [58]).

Decision
[40] We shall allow the reclaiming motion, recall the interlocutor of the Lord Ordinary dated 9 March 2012, and remit the case to the Outer House to proceed as accords, and in particular to hold a proof before answer on the question of prescription and the effect of section 11(3).