Hookway & Anor v R

A genuine disagreement between reputable experts about the strength of DNA evidence does not require the evidence to be withdrawn from the jury. Where each expert accepts that the other’s approach is scientifically valid, and there is other relevant evidence, the jury may assess the competing opinions and give each the weight it considers appropriate. The exceptional caution concerning unresolved scientific knowledge and expert disagreement in unexplained infant-death cases does not automatically govern forensic DNA evidence. A summing up is adequate if it fairly identifies the competing expert views and makes clear that the DNA evidence alone may not prove participation in the offence.

The appellants were convicted at the Crown Court at Leeds of a violent robbery involving the theft of cash cassettes from a supermarket. The prosecution relied in part on DNA profiles recovered from a stolen Mercedes used as a getaway vehicle. Each appellant accepted that he might previously have been in the vehicle, but denied involvement in the robbery.

The prosecution and defence experts disagreed about the statistical evaluation of low copy number DNA results. The trial judge declined to withdraw the evidence from the jury and later directed the jury on the competing opinions. The appellants appealed against conviction, contending that the DNA evidence was unsafe to leave before the jury and that the summing up was deficient.

1. Appeals dismissed. The trial judge was entitled to leave the DNA evidence to the jury. The experts disagreed about the strength and statistical evaluation of the DNA findings, not about whether the findings gave any support for the proposition that the appellants’ DNA was present.
2. The court distinguished R v. Cannings [2004] Cr. App R. 7, CA. That authority concerned unexplained infant deaths at the frontiers of scientific knowledge and a serious dispute about cause of death. In the present case, the prosecution did not depend exclusively or almost exclusively on the disputed DNA evidence, especially in Noakes’s case. Dr Sharpe’s methodology was not alleged to be unscientific, misconceived or fallacious.
3. A jury may evaluate competing, scientifically tenable expert opinions and decide the weight to give them. It was open to this jury to regard the defence expert as unduly cautious and to assess the DNA evidence with the other evidence. The appellants’ acceptance that they might have been in the Mercedes, and the jury’s possible rejection of their innocent explanations, were relevant to that assessment.
4. The summing up was not defective. The judge gave the conventional direction on expert evidence, accurately summarised the disagreement, and made clear that acceptance of the defence expert’s view meant that the DNA evidence did not itself prove involvement in the robbery.

• Court of Appeal (Criminal Division) — dismissed the appellants’ conviction appeals in [2011] EWCA Crim 1989.
• Crown Court at Leeds — convicted both appellants of robbery before Judge Magill and a jury.