Cleobury, R. v

Expert evidence should ordinarily be called at trial. An appellate court will not permit a party to re-litigate expert evidence merely by obtaining a later report which criticises the trial evidence or the conduct of the case.

Fresh expert evidence may be received where the interests of justice require it, such as after a material scientific development despite proper diligence. An expert instructed after trial must remain within the expert’s field and provide independent evidence, not an advocate’s critique of the summing up or the significance of the evidence in the case.

The applicant was convicted by a jury at Swansea Crown Court of rape and sentenced to six years’ imprisonment. The prosecution case included identification evidence, supporting factual evidence and limited DNA evidence.

After conviction, the applicant obtained a new forensic scientist’s reports criticising the trial experts, the absence of a statistical assessment, the scientific evidence about DNA transfer, and the judge’s summing up. A Single Judge refused permission to appeal. The applicant renewed the application, seeking to adduce the reports as fresh evidence.

The central issues were whether the proposed DNA evidence should be received and whether the conviction was unsafe.

1. The renewed application for permission to appeal was refused. The conviction was unarguably safe. There was strong identification and other evidence capable of supporting the verdict independently of the DNA evidence.

2. Fresh expert evidence is not a means of re-litigating evidence that should have been called at trial. The court may receive it where the interests of justice require, including where a new scientific development or other matter emerges despite proper diligence. No such circumstance arose here.

3. The trial experts had properly narrowed the scientific issues in accordance with Criminal Procedure Rules, Rule 33. The proposed report did not reveal a material defect in their evidence. The inability to calculate a match probability had been fairly presented; the challenge to the agreed evidence about DNA transfer lacked a sufficient scientific foundation; and other speculative sources of secondary transfer had not been pursued at trial for sound forensic reasons.

4. An expert instructed after trial must confine the report to matters within the expert’s sphere of expertise. The expert must not provide an advocate’s critique of the conduct of the trial, the summing up, or the importance of the scientific evidence. The new report had improperly crossed that boundary and read more like submissions than independent expert evidence.

5. Accordingly, the proposed evidence could not make the conviction unsafe and did not justify reopening the DNA issues on appeal.

• Court of Appeal (Criminal Division): The court refused the renewed application for permission to appeal against conviction.

• Single Judge: Permission to appeal was refused before the renewed application.

• Crown Court at Swansea: The applicant was convicted of rape on 26 February 2010 and sentenced to six years’ imprisonment.