Mr Justice Chan PJ: 1. I agree with the judgment of Mr Justice Bokhary NPJ. Mr Justice Ribeiro PJ: 2. I agree with the judgment of Mr Justice Bokhary NPJ. Mr Justice Bokhary NPJ: 3. The result of this appeal, which was dismissed at the conclusion of the hearing for reasons to follow, turned on how the Court resolved the dispute between the parties on two aspects of the Employees’ Compensation Ordinance, Cap.282. Of these, the first is the meaning of the expression “personal injury by accident” in s.5(1). And the second is the effect of the presumption laid down by s.5(4)(a). 4. Section 5(1) renders an employer liable to pay employees’ compensation “if in any employment, personal injury by accident arising out of and in the course of the employment is caused to an employee”. It was contended on behalf of the deceased employee’s widow that the accident and the injury can be one and the same event. On the employer’s behalf, however, it was contended that the accident must be distinct from the injury which it caused. Not assisted by any presumption 5. As for the presumption laid down by s.5(4)(a), it is that “an accident arising in the course of an employee’s employment shall be deemed, in the absence of evidence to the contrary, also to have arisen out of that employment”. It was argued on the widow’s behalf that this presumption operates so that where injury occurs at work there is placed on the employer an onus to adduce evidence to the effect that the injury was not caused by accident. But as was pointed out in the High Court of Australia by Fullagar J in The Commonwealth v. Hornsby (1960) 103 CLR 588 at p. 597, the question of whether the injury was by accident is distinct from, and logically anterior to, any question of whether what has happened arose out of or in the course of the employment. So this presumption does not go to the distinct and anterior question of whether the injury was by accident. 6. Not being assisted by any presumption, all that the widow had left was her argument that the accident and injury can be one and the same event. Why the widow was driven to resorting to that argument will emerge once the circumstances of the present case are noted. Shortly stated, they are as follows. Circumstances of the case 7. The deceased, who was aged 37 at the time of his death, was employed by the respondent company in Hong Kong as a merchandiser and had been sent by it to work at its factory in Dongguan City in the Mainland. On 13 July 2007 he was at work. He spent the morning meeting customers in his office at the factory. For lunch, he had a box sent in. After lunch, he resumed work in his office. At about 3:13pm he was talking to a customer on the telephone. Not long after that, he went to the toilet in the office block. After he had been away from his desk for some time, a number of his colleagues went to the toilet to look for him. At about 3:30pm they found him slumped on the floor in the toilet. 8. There was blood in his mouth and nose, and a laceration on the left side of the bridge of his nose. Some blood was seen on the floor. He was rushed to hospital, arriving at about 4:00pm. Upon arrival he was found to have stopped breathing and his heart was found to have stopped beating. The attempt to resuscitate him having failed, he was certified dead at 4:30pm. By a medical report issued that day, the hospital stated the cause of his death as “sudden cardiac death”. But by a supplemental medical report issued on 25 February 2010, the hospital said that the expression “sudden cardiac death” was meant to mean no more than that his heart had stopped beating for some unknown cause, and that the hospital was unable to certify the cause of his death. 9. No autopsy has ever been carried out on the deceased. None was carried out in Dongguan. Nor was any carried out after his body was brought back to Hong Kong on 18 July 2007. He was cremated in Hong Kong on 2 August 2007. 10. Each side instructed an expert in pathology to investigate into and report on the cause of the deceased’s death. These two experts, Professor Annie Cheung and Dr S L Beh, investigated into that on the basis of the deceased’s medical history as disclosed by his medical records. They have produced a joint report. 11. As disclosed by these records, the position was as follows. The deceased had a history of polyposis of the colon which was probably hereditary. He had suffered from pulmonary tuberculosis which resulted in permanent damage to his lungs. That was evidenced by fibrosis and scarring. He was a mild asthmatic. There was evidence of pulmonary emphysema. Two episodes of his having coughed blood had been investigated at St Teresa’s Hospital. And there had been an episode of tension pneumothorax requiring the insertion of a chest drain. 12. The two experts found no evidence of malignancy of the lungs or the colon. Nor did they find any evidence of heart disease or congenital heart condition. 13. Ultimately the two experts reached a conclusion which they summarized thus in their joint report: “There is really insufficient factual information to allow for the determination of a reasonable cause of death. There is no evidence to the suggest that the death was due to a pre-existing congenital or hereditary condition or related to his previous medical conditions. Neither is there evidence to suggest that the death was a result of his employment.” 14. The upshot is that nobody knows the cause of the deceased’s death. 15. On her own behalf and on behalf of the other members of his family, the deceased’s widow brought a claim against his employer for employees’ compensation. 16. That claim was dismissed by the District Court (Her Honour Judge H C Wong) on 25 October 2010. And the widow’s appeal to the Court of Appeal was dismissed by that court (Cheung CJHC, Tang VP and Yuen JA) on 4 July 2011. Injury by accident 17. We were asked to reverse the Court of Appeal’s dismissal of the widow’s appeal to them against the District Court’s dismissal of her claim. The human sympathy due to the deceased’s family is obvious. But as a matter of law, the claim was met by an insuperable difficulty due to the fact that the cause of the deceased’s death is unknown. The expression “injury by accident” plainly encompasses cause and effect, with accident as the cause and injury as the effect. Without a known cause of death, the injury can hardly be found to be an injury by accident. Contending for a concept of accident and injury as one and the same event is to say that cause and effect can be one and the same thing. Axiomatically they cannot. In the course of his skilful agreement that they can be one and the same thing, Mr Denis Chang SC for the widow has sought to place reliance on a number of judicial statements made in cases where the employee had a pre-existing medical condition. But Mr Chang could point to only one claim which succeeded otherwise than on the basis that the work was at least a contributory cause of the injury. 18. That one case is Pang Chew Kim v. Wartsila Singapore Pte Ltd [2012] 1 SLR 15 decided by Tay Yong Kwang J in the High Court of Singapore. In that case the employee died of cardiac arrest, and there was no evidence that any work caused or contributed to that. Nevertheless Tay Yong Kwang J held that employees’ compensation was payable. In so holding the learned judge was following what he understood to be the view of the law taken by Sundaresh Menon JC in an earlier case decided by the High Court of Singapore, namely NTUC Income Insurance Co-operative Ltd v. Next of kin of Narayasamy, deceased [2006] 4 SLR 507. 19. In Narayasamy’s case the learned judicial commissioner said (at para. 24) that the word “accident” included “an internal medical condition that caused an unexpected injury while the workman was carrying out his work”. But he said that immediately after quoting (in para. 23) a passage from the speech of Lord Loreburn LC in Clover, Clayton & Co. Ltd v Hughes [1910] AC 242 at pp 245-246 (erroneously naming instead Fenton v Thorley & Co, Ltd [1903] AC 443). And that passage ends with the examples of the straining of a muscle by lifting a weight or the breaking a blood vessel while tightening a nut with a spanner. Clearly that was directed to the work being at least a contributory cause of the injury. And in Narayasamy’s case, as can be seen from concluding paragraph of Sundaresh Menon JC’s judgment, there was evidence that the heart attack from which the employee died was “triggered by his exertions at work”. That was the basis of the learned judicial commissioner’s decision that employees’ compensation was payable, he having said this earlier (at para. 46) in his judgment: “It does not matter whether that which was done entailed a level of exertion that was beyond that to which the workman was accustomed. It also does not matter that the workman had a pre-existing medical condition such that the injury could have happened at any time, even in his sleep. What is material is that something in fact transpired in the course of his work which made the injury occur when it did.” 20. Pang’s case does not achieve for Mr Chang what he sought to get from it. 21. It is undoubtedly the law that the accident must be distinct from the injury, with the accident being at least a contributory cause and the injury being the effect. Conclusion 22. For the foregoing reasons, this appeal had to be dismissed and was dismissed. Without opposition, an order has been made awarding the costs of the appeal to the employer. And legal aid taxation of the widow’s own costs has of course been ordered. The understandably disappointed widow should know that Mr Chang, his learned junior and those instructing them have done everything they could possibly do in trying to obtain compensation for her in this sad case. Mr Justice Hartmann NPJ: 23. I agree with the judgment of Mr Justice Bokhary NPJ. Lord Hoffmann NPJ: 24. I agree with the judgment of Mr Justice Bokhary NPJ. Mr Justice Chan PJ: 25. Those are the reasons why the appeal was dismissed. Mr Denis Chang SC and Mr Hectar Pun, instructed by Paul C.K. Tang and Chiu and assigned by Legal Aid Department, for the appellant widow Mr Michael Thomas SC and Mr Samuel Chan, instructed by Clyde & Co., for the respondent employer