The Northern Ireland Police Ombudsman, Mrs Nuala O'Loan, is to be called in to inquire into a Belfast Special Branch commander's claim that he was forced out by MI5.
The Northern Ireland Policing Board has called in Mrs O'Loan to deal with Mr Bill Lowry's potentially devastating allegations.
Chief Supt Lowry led the operation that uncovered a suspected IRA spy ring at the heart of the Northern Ireland government last October.
The raids at Stormont led to the suspension of the power-sharing administration and left unionists bitterly sceptical about dealing with republicans again.
But weeks later Mr Lowry quit the force, claiming he had been betrayed and humiliated.
He wrote to the board demanding they investigate his allegations that a phone call from London led to his removal days after a major row flared inside the Police Service of Northern Ireland's headquarters over the anti-IRA operation.
Mr Lowry claimed he was forced out to appease Sinn Féin because he had arrested prominent republicans during the intelligence raid.
But Chief Constable Hugh Orde has rejected any suggestion that it came under political pressure to get rid of the Special Branch officer.
Mr Lowry's letter of complaint had been passed to Mrs O'Loan's office, but she sent it back saying that it had not been referred to her under the proper legislation.
The 19-member body was then split over whether an independent investigator should be called in or have the matter returned to the Ombudsman under the correct rules.
But it is understood that at a sub-committee meeting in Belfast today board chairman Prof Desmond Rea argued that it was a high-profile case that must be investigated by Mrs O'Loan.
PA