Why more than 1,700 drug-driving prosecutions could be overturned

More than 1,700 drug-driving prosecutions have been thrown into doubt after a review found the results of hundreds of lab tests were wrong.

Problems with tests carried out by Synlab Laboratory Services Limited were identified by the company in December 2020 and a review by police and the forensic science regulator has now found several hundred results will have to be withdrawn as evidence.

On Monday, the National Police Chiefs’ Council (NPCC) announced that all drug-driving tests produced by Synlab between April 2019 and December 2020 where levels were found to be above the prescribed limit must be withdrawn.

In that time period, the company analysed 4,255 samples, of which 2,181 had no drug present or a level of drug below the prescribed limit. There were 296 samples from cases which were discontinued or there was no conviction at court.

The remaining 1,778 samples had drug levels reported by Synlab to be above the prescribed limit, but these results have now been withdrawn.

NPCC lead for forensics, Chief Constable Nick Dean, said: “This has been a lengthy and in-depth review, which I know has been hugely challenging for those individuals who are impacted by the results.

“I would like to commend their patience while we have worked through the data. The reviews were done at such a detailed level because we are committed to ensuring evidence entering the courts is reliable.

“We take any issues seriously and wanted to ensure due diligence was taken to achieve the correct outcome.

“Synlab have been very forthcoming and open during the reviews, which we welcome.

“I want to thank all our partners who have spent many hours reviewing and working hard to try and get this right.

“It is hugely regrettable whenever evidence that has been submitted to the courts in good faith has to be withdrawn. We know that this will have significant knock-on effects for people.”

The Crown Prosecution Service is in the process of contacting those whose samples have been withdrawn.

Darryl Preston, forensic lead for the Association of Police and Crime Commissioners, said: “This review has taken some time, however it was crucial to ensuring it was carried out meticulously with the proper resolution.

“There is no doubt this will have been a challenging time for all those affected, and I would like to praise them for their patience. It is vital that all evidence entering the courts is unfailing and it is for that reason that we ensured the review was conducted to the highest standard.

“We are disappointed that cases have been rescinded and the implications this has on justice, but we welcome the Forensic Science Regulator’s review of these cases.”

Reporting by Press Association