Cambridgeshire Police are investigating concerns of alleged manipulation at a forensics lab that analyses evidence of drug driving, violent crime, sexual offences and unexplained deaths.

The county’s force instigated a review earlier this year after allegations came to light in connection with forensic toxicology tests carried out by Randox Testing Services.

Bedfordshire, Cambridgeshire and Hertfordshire Police (BCH) say it is a nationwide issue.

Superintendent Russ Waterston, deputy head of BCH criminal justice and custody unit, said: “We have reviewed samples dating from late 2013 to early 2017.

“To date, we have identified 129 criminal cases, which equates to 211 forensic samples across Bedfordshire, Cambridgeshire and Hertfordshire, that may have been affected by this issue.

“These cases cover a wide variety of offences.

“The majority relate to road traffic offences but there are also cases relating to violent crime, sexual offences and sudden deaths.

“In line with the national response, the most urgent cases, including those that are currently going through the criminal justice system, are being given retesting priority.

“To date 22 samples have been re-tested and the results have remained unchanged.

“As we progress with this review we will of course ensure that contact is made via the Crown Prosecution Service with anyone who has been affected by inaccurate samples.

“Understandably, this news will cause concern but I would like to reassure the public that it is very unusual that one single strand of evidence, such as toxicology results, would form the entire basis of a case.

“There is normally other significant evidence that supports the decision making of the police, the Crown Prosecution Service and the courts.

“We are continuing to work closely with the NSPCC, the Home Office and the Crown Prosecution Service and our priority is to ensure the integrity of the criminal justice system.”

Police are working with partners including, the National Police Chiefs’ Council (NPCC), the Home Office and the Crown Prosecution Service. In Cambridgeshire they ahe so far looked at 45 cases which involved a total of 66 samples.