The former chief reporter of the News of the World has been approached by Scotland Yard to give evidence in the phone-hacking scandal against his former employer.
Neville Thurlbeck, a key figure in the crisis that has engulfed Rupert Murdoch's News International, said that detectives from a specialist Yard unit last week asked him turn "Queen's evidence" in return for possible immunity from prosecution.
The move represents a dramatic twist in the Metropolitan Police inquiry into voicemail interception at the now-defunct Sunday tabloid, suggesting that 11 months of investigation has led detectives to conclude Thurlbeck is more useful as a potential witness against senior figures in the Murdoch empire.
Late last night James Murdoch was appearing before MPs to help explain why he failed to tell them of discussions he had with the News of the World editor on the "options" they faced over phone hacking.
The News International chairman was appearing for the second time before the Commons Culture Committee. Jeremy Sandelson, head of litigation for law firm Clifford Chance, had been tutoring James Murdoch to expect what one MP predicted would be "an assault on his credibility".
A total of 16 people, including Thurlbeck, former News chief executive Rebekah Brooks and former NOTW editor Andy Coulson, have been arrested on suspicion of taking part in a phone-hacking conspiracy at the title. But with many suspects bailed until next March, it is understood the investigation, which has so far uncovered the names of 5800 possible victims, still has a long way to run.
Thurlbeck, who rejected the proposal, was arrested in April along with the NOTW's former news editor Ian Edmondson on suspicion of conspiring to unlawfully intercept mobile-phone messages.