The defence secretary has apologised to Parliament over his working relationship with close friend Adam Werritty, telling MPs he would "fully and willingly" co-operate with the internal investigation into his conduct.
Liam Fox revealed in a statement to the Commons on 10 October 2011 that he had met his former flatmate and best man 18 times on foreign trips - including holidays - and 22 times at the Ministry of Defence, the majority "short social meetings".
Mr Werritty, 34, also used to carry cards describing himself as an adviser to "the Rt Hon Liam Fox MP".
Mr Fox assured MPs that Mr Werritty did not have access to classified documents nor was he briefed on classified matters, and he said that such meetings and trips would end.
The defence secretary admitted it had been "a mistake to allow distinctions to be blurred between my professional responsibilities and my personal loyalties to a friend".
But shadow defence secretary Jim Murphy accused Mr Fox of driving a "coach and horses" through the ministerial code of conduct.
He said the "crisis" was "self-inflicted" and that many would "doubt the judgement of the secretary of state who allowed himself to be compromised in this manner".
Mr Murphy called for all relevant information about Mr Fox's meetings with Mr Werritty, and any advice he received from civil servants about their working relationship, to be published because "the only way to clear his name is for total transparency".
Earlier on Monday Prime Minister David Cameron said he had full confidence in Mr Fox who had been a "very effective" defence secretary.