Image caption Andrew Rennison said the re-use of plastic trays in LGC's laboratories 'failed to follow basic procedures'

Forensic procedures carried out by a private firm which wrongly linked the DNA of a man to a rape were "not adequate", a report says.

Adam Scott, from Devon, was held for a couple of months after being accused of raping a woman in Manchester.

The charges were dropped when it emerged a DNA sample had been contaminated at LGC Forensics.

Forensic Science Regulator Andrew Rennison said Mr Scott was an "innocent victim of avoidable contamination".

LGC Forensics said that it "deeply regrets the incident of contamination".

Mr Scott was charged in 23 October 2011 after a plastic tray containing a sample of his DNA was re-used in the analysis of a swab from a rape victim in Plant Hill Park, Blackley. The result of that test linked him to the crime.

The report said police investigating the rape allegations raised concerns seven weeks later because phone records suggested Mr Scott had been in Plymouth a few hours after the alleged attack.

Analysis In March this year, the government wound up the Forensic Science Service, leaving private companies and police laboratories to take on its work. That month, news emerged of the DNA mix-up involving Adam Scott at the Teddington lab of the biggest private provider, LGC. Critics of the FSS closure claimed it was no coincidence. LGC had bitten off more than it could chew, they said - pointing to a Science and Technology Committee report the previous year warning that the private sector lacked the capacity to absorb the FSS's market share. Andrew Rennison's report, however, suggests it was more to do with human error and lax procedures, following the introduction of new robotic equipment. No other cases of contamination have been identified. It is also worth recalling that DNA blunders are not unique to the private sector - the FSS had its fair share too.

The rape charges were eventually dropped in March 2012.

A few days later Mr Scott said in a statement that he was "angry that I was falsely accused [and] am angry about the amount of pain it has put me and my family through".

Mr Rennison's report said that the contamination was the result of human error by a technician who "failed to follow basic procedures for the disposal of plastic trays used as part of a validated DNA extraction process".

He also said that the procedures themselves were not adequate, which also meant that records were not being maintained by the technicians and nothing was being done to mark trays once they had been used.

He went on to say that some 26,000 other samples have been checked and no further errors had been identified.

The re-use of plastic trays was identified on 11 October 2011 and should have triggered a more comprehensive response than that undertaken, the report added.

'Corrective actions'

"These errors were compounded by the failure at LGC to consider the possibility of contamination despite concerns expressed by the investigating officer about the reliability of the DNA profile," Mr Rennison said.

Find out more Radio 4's The Report investigates the state of the forensic science industry in the UK and speaks to a man wrongly accused of murder because of flawed DNA testing. Listen via the Radio 4 website Listen via The Report download

A Home Office spokesman said: "Andrew Rennison's independent report has found the incident was caused by human error and failures at LGC Forensics to respond to warning signals.

"Both he and the UK Accreditation Service are content that processes have been put in place to stop this happening again."

But Mr Scott's mother, Michelle, told BBC Radio Devon that "all procedures" at forensic firms such as LGC needed to be improved.

"They need to make sure that everything they're doing is checked and double-checked to make sure that everybody has a fair chance."

She added: "I would not wish this on anybody or anybody's family - what we've had to go through for five whole months."

A spokesman for LGC Forensics said: "The Forensic Regulator and the United Kingdom Accreditation Service have expressed their satisfaction with our investigation into the incident, the corrective actions and LGC's overall contamination avoidance and checking processes.

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"LGC treats incidents like this with utmost seriousness and we look forward to continuing to provide excellent forensic services to the Criminal Justice System."

Speaking to BBC Radio 4's PM programme, Mr Scott's solicitor, Philippa Jefferies of Rundle Walker Solicitors, said it had left her "dumb-struck that this could happen".

She said: "I'm sure [LGC] are very, very sorry it's happened because it's a black stain - a terrible fundamental error.

"[In] being responsible for processing DNA material that may result in convicting or acquitting a defendant, it must be of paramount importance that safeguarding issues and risk assessments [are taken seriously]."

The government's decision to close the Forensic Science Service (FSS) in England and Wales in March was criticised by the cross-party House of Commons science and technology committee, which said the government had not given sufficient consideration to the wider impacts of its closure.

And the forensic science archive, while still in use, stopped accepting new material as a result of cost cutting from March.

The changes to the archive, which holds more than 1.7m case files, mean forces now have to create individual storage systems for forensic material.