DOZENS of motorists found guilty of drug driving in Essex could have their convictions quashed because of suspected tampering at a forensics lab.

Essex Police is writing to drivers whose tests were carried out by Randox Testing Services (RTS), based in Manchester.

Greater Manchester Police (GMP) arrested two men this week, aged 47 and 31, on suspicion of perverting the course of justice.

It is thought that almost 500 people nationwide could have been the victims of miscarriages of justice because of convictions based on incorrect toxicology test results.

Following an internal investigation, the firm said the manipulation was of quality control data, rather than the samples themselves.

It said no alcohol samples were affected, and some tests could be “rerun to provide robust, uncompromised results”. Police are looking into the possibility that a disgruntled employee fiddled the results deliberately.

The Echo asked Essex Police how many cases in the force’s area were affected and whether any involved a custodial sentence.

A spokesman declined to give specifics and said: “Essex Police is reviewing a small number of cases where it is believed these may have been compromised by data integrity issues which have recently come to light in regard to Randox Testing Services (RTS). We will review each case to ascertain if compromised data played a key part in prosecution and will work with the CPS to determine if further action needs to be taken.”

A spokesman for the Crown Prosecution Service said: “We are working with the Home Office, police and the Office of the Forensic Science Regulator to assess the impact of the issue with Randox Testing Services. This includes establishing which cases have been affected by this issue and working with other agencies to decide what action should be taken in relation to those cases.‎”

Elsewhere in the country, one drug-driving case involving a 26-year-old man from Chester has already been dropped following a review of blood test data.

A spokesman for RTS said: “We are working with the Home Office, police and the Office of the Forensic Science Regulator to assess the impact of the testing failure at Randox Testing Services.

“This includes establishing which cases have been affected by this issue and working with other agencies to decide what action should be taken in relation to those cases.‎”

A spokesman for GMP said: “Randox Testing Services has provided forensic services to police forces, including GMP, for the past two years. The organisation is being fully cooperative [with] the investigation.”