Broughton, R. v

Low Template DNA evidence obtained from less than 100 or 200 picograms is not automatically inadmissible. The court must apply the ordinary requirements of reliability and relevance to the established scientific field. Wholly unreliable profiles must be excluded, but genuinely debatable evidence may be admitted and tested by adversarial evidence.

Where the Crown’s DNA statistics depend on an expert’s interpretation of a profile, and the jury reject that interpretation, the jury cannot assess the evidence without alternative expert statistics. The evidence must then be disregarded and, where it is essential to the Crown’s case, the jury must be directed to acquit.

Following a retrial at the Crown Court at Oxford, Mel Broughton was convicted of conspiracy to commit arson arising from attacks using incendiary devices with sparkler fuses. The Crown relied centrally on Low Template DNA evidence recovered from match stalks at one scene, together with other circumstantial evidence.

The appeal challenged the admissibility of the DNA evidence, the judge’s directions about its statistical significance if the Crown scientist’s interpretation was rejected, the retention of a juror employed in a clerical role by Cellmark, and the admission of evidence of sparklers found at the appellant’s home. The central issue was whether the jury could evaluate the DNA evidence after rejecting the interpretation on which the Crown’s match statistics depended.

1. Appeal allowed. The conviction was unsafe because the jury may have evaluated DNA evidence without any expert basis on which to assess its probative force.

2. The trial judge had applied too low a test for admitting expert evidence. Applying Reed & Reed [2009] EWCA Crim 2698, the court held that the relevant question was whether the field formed a sufficiently recognised and reliable body of knowledge and whether the evidence was relevant. Low Template DNA below the stochastic threshold was not inadmissible as a class. The particular profiles were admissible: the techniques were established, the process had been repeated, and the reliability dispute could properly be tested at trial.

3. The summing-up nevertheless contained a decisive error. Under the approach in R v Doheny; R v Adams [1997] 1 Cr.App.R. 369 and R v Bates [2006] EWCA Crim 1395, jurors required sufficient expert guidance to evaluate DNA evidence and its limitations. If they rejected Ms Hammond’s interpretation that the profile was single rather than mixed, the Crown’s match-probability figures were invalid. As the Crown had supplied no alternative statistics, the jury could not make their own statistical assessment. They should have been directed to disregard the DNA evidence and acquit.

4. The apparent-bias ground failed. A fair-minded observer would not perceive a real possibility of partiality from a juror’s clerical employment by Cellmark where she had no scientific role, did not know the relevant director, and his evidence was only part of the Crown’s expert case.

5. The court also refused leave to challenge the admission of sparkler evidence. The judge had been entitled to decline exclusion under section 78 of PACE because the evidence had clear probative value.

6. The court added, obiter, that advocates and experts must not allege a forensic expert’s lack of integrity without an evidential foundation.

• Court of Appeal (Criminal Division) — Allowed the appeal against conviction because the jury had not received a legally adequate direction on the consequences of rejecting the Crown expert’s interpretation of the DNA profile.
• Crown Court at Oxford — At a retrial before HH Judge Eccles QC and a jury, the appellant was convicted on 13 February 2009 of conspiracy to commit arson and sentenced to 10 years’ imprisonment less time on remand. At the earlier trial, the jury had not reached verdicts on the conspiracy and possession counts and had acquitted on the sparkler count.