R v Yusf Mahamed Ali

Fresh expert evidence is exceptional where it could and should have been adduced at trial. Section 23 of the Criminal Appeal Act 1968 does not generally permit an appellant to advance on appeal an expert case that should have been presented to the jury. The court should consider whether the expert analysis rests on assumptions inconsistent with the trial evidence and whether the jury already had relevant material, such as photographs or video. Those limitations may mean that the new evidence cannot make the conviction arguably unsafe. Where permission to appeal is refused on its merits, a separate application for an extension of time need not be determined.

The applicant was convicted of causing grievous bodily harm with intent, affray and possession of a bladed article. He sought to rely on fresh evidence from an engineer and falls expert concerning the mechanics of the complainant’s fall from a balcony. The single judge refused leave to appeal against conviction, citing the unexplained delay, the availability of the evidence at trial and the limitations of the expert report.

The applicant applied to renew the permission application and sought a further seven-day extension of time. The central issues were whether the fresh evidence should be admitted under section 23 of the Criminal Appeal Act 1968 and whether the conviction was arguably unsafe.

Application refused. The court agreed with the single judge and refused the application to renew permission to appeal on its merits. It was therefore unnecessary to consider the extension of time.

1. Fresh expert evidence. Section 23 of the Criminal Appeal Act 1968 was enacted to protect against wrongful conviction, but it does not generally contemplate allowing a convicted defendant to present on appeal an expert case that could and should have been advanced at trial. As explained in R v Jones [1997] 1 Cr App R 86, expert witnesses are interchangeable in a way that factual witnesses are not. A general freedom to deploy a new expert case on appeal would subvert the trial process.
2. Exceptional nature of the evidence. The court adopted the single judge’s reliance on R v Erskine [2009] EWCA Crim 121, that it is exceptional to admit on appeal evidence which could and should have been advanced at trial. No satisfactory explanation had been given for the substantial delay or for failing to obtain comparable evidence at trial.
3. Limitations of the report. The proposed expert evidence assumed that the complainant had been standing on flat feet, whereas her trial evidence was that she had been leaning over the balcony. That factual discrepancy materially limited the force of the report. The complainant had also been cross-examined, and the jury had access to photographs, a 360-degree presentation and video footage of the area. In those circumstances, it was not arguable that the conviction was unsafe.

1. Single judge: refused leave to appeal against conviction and refused an extension of time, citing the unexplained delay, the availability of the expert evidence at trial and the absence of any arguable unsafe conviction.
2. Court of Appeal (Criminal Division): in [2025] EWCA Crim 597, refused the renewed application on its merits. The court did not consider the further extension of time.