A street in Belfast during the Troubles (Picture: PA).
A police chief who is investigating the Army's top-ranking IRA agent told the Prime Minister she "got it wrong" on legacy cases in Northern Ireland.
Outgoing Bedfordshire Chief Constable Jon Boutcher said he wrote to Theresa May after she told the Commons last year that only people in the security forces were being subjected to historic Troubles investigations.
Mr Boutcher, who is leading the probe into Stakeknife, made the comments in a UTV special programme on the legacy of the conflict being aired on Monday night. He said:
"The Prime Minister got it wrong and I wrote to her to correct her."
Mr Boutcher, who unsuccessfully applied to become Northern Ireland's next police chief, is leading the Operation Kenova investigation into Stakeknife, a high-ranking mole who reputedly ran the IRA "nutting squad", which interrogated and murdered suspected informers.
In 2003, Stakeknife was widely named as west Belfast man Freddie Scappaticci, but he has always strongly denied it, and rejects claims that he was an IRA informer.
Mr Boutcher told UTV's Lasting Legacy programme that Mrs May's remarks had raised questions for relatives of Stakeknife's alleged victims.
"I have a trust with the families, if the families see those sorts of comments from our Prime Minister there is obviously going to be a dilemma as to who they believe," he said.
"So I wrote to the Prime Minister who I had already spoken to about Operation Kenova and made it very clear we are investigating the IRA and any wrongdoing by the security forces. So I wrote to her to remind her of that and put the record straight and I informed the families to reassure them that I was doing what I said I was going to do."
He said Mrs May's office wrote back to him but he declined to outline details of the reply.
Lord Chief Justice Sir Declan Morgan said when the Good Friday peace deal was brokered back in 1998, the legacy issue was put in a box marked "too difficult". He said:
"We've got to take it out of that box, we've got to address it.
"And I think we have paid the price of not being able to address it 20 years ago."
The Government recently released £55 million to finance a new legacy unit to process around 50 outstanding inquest cases relating to almost 100 historic Troubles deaths.
Sir Declan, who had proposed the unit, said he acknowledged that families who were waiting for other stalled legacy mechanisms to be established, such as an independent investigation unit, would be frustrated at ongoing delays.
A UK Government spokesman said: "The system to investigate the past in Northern Ireland needs to change. The Government is committed to creating a system that works for everyone, which is why we have consulted widely. We received over 17,000 responses to our consultation, and we will set out next steps in due course."