Chattoo & Ors v R

Under section 23 of the Criminal Appeal Act 1968, the decisive question on an application to adduce fresh expert evidence is whether receiving it is necessary or expedient in the interests of justice. The statutory factors must all be considered, but they operate within that overall inquiry.

Ordinarily, an appellant cannot use the appeal to advance an expert case which could and should have been advanced at trial, replace an available expert with a more favourable one, or deploy evidence previously withheld because it assisted the prosecution. Exceptional circumstances may include incompetence by the trial expert or wholly unreasonable conduct by the legal team. A later expert’s differing emphasis will not ordinarily justify reception where the trial expert was competent and the material was available at trial.

The four appellants were convicted at Sheffield Crown Court before Griffith-Williams J of the murder of Tarek Chaiboub. The prosecution alleged that a recovered sawn-off shotgun was the murder weapon and relied on firearms and ammunition evidence to connect it with the killing and the appellants.

At a later, connected trial, a different firearms expert gave evidence and the prosecution expert was cross-examined more extensively. The appellants sought to rely on that later expert’s evidence as fresh evidence on appeal. They contended that it showed that the recovered shotgun was not the murder weapon, or materially weakened the prosecution’s forensic case.

The central issue was whether the Court of Appeal should receive the proposed expert evidence under section 23 of the Criminal Appeal Act 1968.

1. The appeals were dismissed. The court held that it was neither necessary nor expedient in the interests of justice to receive Mr Arnold’s proposed expert evidence under section 23 of the Criminal Appeal Act 1968.

2. The controlling inquiry under section 23(1) is the overall interests-of-justice test. In considering whether to receive evidence, the court must have particular regard to the statutory matters in section 23(2): credibility, capacity to afford a ground of appeal, admissibility, and any reasonable explanation for the failure to adduce it at trial.

3. The court reaffirmed the restrictive approach to fresh expert evidence. Save in exceptional circumstances, an appeal cannot be used to run an expert case which could and should have been put before the jury. Nor may it ordinarily be used to substitute a different or additional expert after the defence chose not to deploy available expert evidence. Such a course would undermine the finality and integrity of the trial process.

4. Exceptional circumstances might arise if the trial expert were incompetent, or if the legal team had acted in a way no reasonable lawyers could have acted. Neither condition was established. Mr Dyson was qualified and competent; his instructions covered the relevant forensic issues; and his decisions about the examination of the exhibits were reasonable.

5. Much of the material relied upon by the appellants was known before or during the first trial. The prosecution expert had already accepted that he could not determine whether the shotgun was the murder weapon or how long it had been inoperable. The defence had the material needed to cross-examine him on those matters, but chose not to do so.

6. The later evidence amounted principally to a difference of expert emphasis about the strength of the supporting forensic evidence. The unintentionally misleading description of the test cartridges was immaterial because the relevant wadding was of the same type and the original expert had already found no specific agreement in the striations. The proposed evidence was therefore very doubtful to provide any ground for allowing the appeals.

• Court of Appeal (Criminal Division): dismissed the appellants’ conviction appeals and refused to receive the proposed fresh expert evidence under section 23 of the Criminal Appeal Act 1968.
• Sheffield Crown Court: Griffith-Williams J and a jury convicted the appellants of murder following the trial in July and August 2009.