A drug-driver jailed for killing his girlfriend in a crash has lodged an appeal against his conviction over concerns forensic evidence was tampered with.

Anderson Ward, from Newtown, is attempting to launch proceedings in the Court of Appeal after it emerged that scientists allegedly manipulated lab data.

The revelations sparked a major review of more than 10,000 criminal investigations, so far leading to around 50 prosecutions being dropped.

Ward, 39, was jailed for six years in February after being found guilty of causing death by careless driving while on drugs, causing death by driving a vehicle unlicensed and possession of Class B and C drugs.

His girlfriend Marie Hardes, 56, was killed after Ward lost control of the vehicle they were travelling in, on the M3 in Winchester in November 2014.

Ward is one of two killer drivers trying to have their convictions quashed, but it is anticipated that more appeals will follow as thousands of toxicology tests are re-analysed.

Three-quarters of the cases being re-examined involve traffic offences such as drug driving – with the rest including violent crime, sexual offences and unexplained deaths, spanning back to 2013.

Two men have been arrested and five interviewed under caution by Greater Manchester Police over the alleged manipulation by individuals working at a Randox Testing Services (RTS) site in Manchester.

Potential data manipulation at a separate facility, Trimega Laboratories, is also being investigated by Greater Manchester Police – affecting child protection and family court cases, the National Police Chiefs’ Council said.

It is understood the two suspects arrested in connection with the alleged malpractice also worked for Trimega.

Deputy Chief Constable James Vaughan, the NPCC forensic expert, said: “This is of grave concern to me, it is of great concern to policing and our partners in criminal justice and we are taking it extremely seriously and provided a nationally co-ordinated and very swift, robust response, to understand more detail.”

It is expected the full retesting process will take two to three years to conclude, with 1,500 samples retested by the end of the year.

The alleged misconduct emerged earlier this year when a data anomaly in a drug driving case was reported to RTS.

Hampshire Police confirmed Anderson Ward had lodged an appeal but it had not yet been granted.

Forensics from 474 cases in the Hampshire Police Force area are being re-examined. Of the 40 samples tested so far, nine results have shown differences and seven are being reviewed to establish whether the results are significantly different.