A former IRA informer who claimed he was threatened by the alleged British agent codenamed Stakeknife was questioned today by the team of detectives investigating collusion allegations in Northern Ireland.
The man known as Kevin Fulton spent an hour with officers from the squad headed by Metropolitan Police Commissioner Sir John Stevens.
They asked to meet him after he alleged 57-year-old west Belfast builder Mr Freddie Scappaticci interrogated him following a failed IRA ambush on a top detective in east Belfast in 1994.
Police arrested a number of terrorists who had been planning to ambush Chief Supt Derek Martindale.
Fulton claimed last week he and another member of his family were interrogated by Mr Scappaticci amid allegations police had been tipped off in advance of the planned IRA attack.
Mr Scappaticci, from west Belfast, has categorically denied he was paid £80,000 annually to be an agent for British military intelligence while a key member of the IRA's so-called internal security squad.
Sir John Stevens has already confirmed he intends to interview Stakeknife.
But Fulton's meeting today in central London was the first direct contact with someone allegedly at the centre of the Scappaticci affair.
Fulton (43) said tonight: "They asked for this meeting and I agreed to it even though I don't have a great deal of faith in the Stevens Inquiry.
"I can't comment on what was discussed because they said the allegations were serious and the investigation was still alive.
"They assured me that my allegations would be fully investigated."
Fulton has denied claims he was behind newspaper allegations identifying Stakeknife but insists Mr Scappaticci detained and questioned him as part of an IRA inquiry into the failed attack on Chief Supt Martindale.
Last month, a report by the Stevens Inquiry found members of the British army and Royal Ulster Constabulary colluded with the loyalist paramilitary group, the Ulster Defence Association.
Up to 20 Army and police personnel could face criminal charges arising out of the report which centred on the murder of Catholic solicitor Mr Pat Finucane in 1989 and Protestant student Mr Adam Lambert in 1987.
PA