DNA pioneer warns that forensic testing is heading for catastrophe

The privatisation of forensic testing in Britain is leading to catastrophic failures and potential miscarriages of justice, the pioneer of mass DNA profiling has warned.

In a damning indictment of the new system of forensic testing in Britain, Professor Peter Gill said the "wheels were already falling off" following the switch to private providers and police labs from the loss-making Forensic Science Service (FSS), which closed its doors for the last time on Friday.

He has called for thousands of criminal cases to be reviewed to prevent miscarriages of justice following high-profile blunders by the country's biggest private testing centre, LGC.

The LGC errors included the cross-contamination of two samples in a lab. In one rape case it led to a false finding that there was a one-in-a-billion chance that an innocent man was not tied to the crime scene. It was revealed last week that the company also accidentally created a non-existent suspect during the inquiry into Gareth Williams, the MI6 worker whose body was found inside a sports bag at his London flat – leading police up a blind alley for more than a year.

The forensic science regulator said it had checked 26,000 samples after the rape case error and had found no other problems. But Professor Gill expressed doubt over the initial inquiry's findings.

"The only way forward is for the courts to individually reconsider the affected cases via the appeal procedure ... otherwise it seems to me that there is a significant possibility of miscarriage of justice within the cases that comprise the affected batch of samples," he said. "I'm surprised that the wheels are falling off so quickly. I didn't think we'd hear anything for two years – not a couple of weeks.

A Home Office spokeswoman said: "The Forensic Science Service was making huge losses as the market for forensic services contracted."

LGC said it took on temporary staff and contractors for a short period during the transfer of work from FSS. It said work was no more fragmented than it ever was.