The British government has mounted a 10-year intelligence gathering operation against top businessmen in Northern Ireland, it was claimed tonight.
Democratic Unionist MLA Mr Ian Paisley Jr said dossiers had been compiled on entrepreneurs and other unsuspecting members of the public.
Bundles of case notes prepared by Northern Ireland Office staff were among files stolen at Stormont, he claimed.
Mr Paisley said: "What has been uncovered is a nest of vipers not only on the Falls Road but also paid agents at the NIO."
The DUP Assembly member's allegations came as detectives today warned him that his details were found among more than 1,200 documents seized last year during raids to smash the suspected IRA espionage plot.
Detailed information on rival Ulster Unionist MP Mr Jeffrey Donaldson was also included on the alleged terror list, it has emerged.
But others alerted by police within the last week were told of personal details dating back years that could be of no interest to republicans, Mr Paisley insisted.
Officers visited a high-profile Northern Ireland businessman and a woman in north Antrim with DUP connections.
Three planning applications linked to the party and the business community were listed on the warning papers, Mr Paisley said.
He added: "The information that was shown to them indicates that for the last 10 years they were being spied on not by the IRA, but by someone at the NIO. "That information fell into the hands of the IRA when they were involved in the spy/theft ring at Stormont."
Four people, including Sinn Féin's administration chief and a messenger employed at former Northern Ireland Secretary Dr John Reid's Belfast offices, have been charged in connection with the suspected IRA spy-ring.