Page:HKSAR v. Wun Shu Fai (CACC 48-2015).djvu/28

Rh “…the prosecution has a duty to ascertain and disclose to the defence relevant material (including information) in its possession or control and in the possession or control of the investigating agency (including the police)…”

Accomplice prosecution witnesses

62. It has been long-established that the prosecution’s duty of disclosure in respect of prosecution witnesses, who themselves are accomplices in the offence the subject of the trial, is of particular importance. In the judgment of this Court in the Queen v Tsui Lai Ying, Silke VP addressed the issue, in the context of prosecution witnesses who had given evidence under immunity from prosecution:

“It is clear beyond peradventure that in cases like this the accomplice is to be presented to the court warts and all. The defence is entitled to know everything about him, the terms of the immunity and any matters surrounding it which will affect credibility of his evidence.”

63. Similar considerations are relevant to cases in which accomplice witnesses gave evidence for the prosecution, albeit not under an immunity from prosecution, where there is a possibility that in so doing a reduction in sentence may be afforded to the accomplice either by an appellate court or the Chief Executive.