PROSECUTIONS of around 100 sub-postmasters by the Department for Work and Pensions (DWP) might be "tainted" due to collaboration with discredited Post Office investigators in securing convictions, a Sky News investigation has revealed.
These legal actions usually involved the cashing in of stolen order books from 2001 to 2006.
The Post Office wrongly prosecuted numerous sub-postmasters between 1999 and 2015, relying on evidence from the flawed Horizon accounting system.
The Sky News investigation found that information was exchanged between Post Office and Department for Work and Pensions (DWP) investigation teams.
Chair of the Justice Select Committee, Sir Robert Neill KC, stressed the need to scrutinise DWP convictions in light of this revelation.
"I hadn't been aware of that, for example, there may have been material in the DWP case as a result of joint investigations - which suggests a disclosure failure," he was quoted as saying.
"I think that's the area they need to look at if we are saying their approach was tainted from the beginning - in the way the investigators adopted things - then joint operations I suspect would be just as tainted arguably as something where it has been the Post Office on its own."
Former MP-turned Tory peer Lord James Arbuthnot, a supporter of scandal victims, expressed similar concerns, intending to inquire further with ministers in the House of Lords.
A 2003 report from the DWP on fraud mentioned collaboration and information sharing with the Post Office. It also revealed the establishment of a 'Fraud Prevention Board' involving the DWP and Royal Mail Group plc to aid in fraud prevention and investigations.
Additionally, a 2003 letter indicated a link between DWP and Post Office investigations, referencing the case of Roger Allen, a sub-postmaster convicted of stealing pension payments in 2004.
He was sentenced to six months in prison, and died in March this year. Allen had pleaded guilty to spare his wife.
Now, Keren Simpson, Allen's daughter, is determined to clear her father's name posthumously, describing him as an honest man.
There were other documents that suggest failures by DWP investigators in a different case in the 2000s. It involved a sub-postmaster who decided to plead not guilty and was acquitted of stealing by a jury.
Another document revealed a failure to review transaction logs used as evidence against the sub-postmaster.
Chris Head, former sub-postmaster and a campaigner, noted that these documents point to a "deeply flawed" DWP investigation.
"…they failed to obtain all transaction logs for the entirety of this case, but the ones that they have, they have they clearly haven't looked at," he said.
A DWP spokesperson said: "We do not recognise these claims. DWP investigates offences against the welfare system to protect taxpayers' money, and between 2001 and 2006 a small number of Post Office staff were convicted for welfare-related fraud.
"These cases involved complex investigations and were backed by evidence including filmed surveillance, stolen benefit books and witness statements - they did not rely on Horizon evidence, and this has been accepted by the Court of Appeal."
Meanwhile, Lord Sikka has proposed an addition to the Post Office (Horizon System) Offences Bill in the House of Lords, aiming to include all DWP convictions.
The Post Office asserts its commitment to aiding other prosecuting bodies by providing comprehensive assistance to advance their work. This entails sharing all relevant information regarding prosecutions initiated by other authorities.
