A police investigation into computer hacking by private investigators working for the press has uncovered evidence that former Prime Minister Gordon Brown’s emails were "illegally accessed" during his time as Chancellor of the Exchequer, according to a report from the Independent.

Operation Tuleta was launched last year to examine email hacking allegations not covered by the investigation into phone hacking by media giant News International.

According to the Independent, the operation has identified Gordon Brown and lobbyist Derek Draper as potential targets, based on evidence from seized computers.

Police are "looking at evidence from around 20 computers which hold data revealing that hundreds of individuals may have had their private emails hacked," the newspaper reported yesterday.

In November last year, a 52-year-old man was arrested in Milton Keynes on suspicion of offences under the Computer Misuse Act, the first arrest by Operation Tuleta.

Former army officer Ian Hurst, who wrote a whistleblowing book about British intelligence forces in Northern Ireland, told Channel 4 News in July last year that Operation Tuleta officers had warned that his family’s email had been accessed.

In December, former Northern Ireland secretary Peter Hain confirmed that he had spoken to Operation Tuleta officers about the potential hacking of his computers.