Conservative MP Patrick Mercer has been accused of breaking parliamentary rules by offering to provide a Commons pass for lobbyists.
The Conservative MP, who is alleged to have lobbied on behalf of Fiji, posed several questions about the country to Parliament this year.
Patrick Mercer MP spent 25 years in the Army before entering politics.
BBC's Panorama show said they have been investigating lobbying and conduct of MPs and members of the House of Lords and sought a response from "a number of people including Mr Mercer." In a statement the broadcaster said:
BBC Panorama has been investigating lobbying and the conduct of MPs and members of the House of Lords.
The programme is still being made and will be broadcast as soon as possible. The investigation has raised a number of issues related to those involved. Panorama has sought responses from a number of people including Mr Mercer.
A Conservative Party spokesman said David Cameron is aware of Patrick Mercer's resignation and thinks he has "done the right thing" in referring himself to the Parliamentary Commissioner for Standards over allegations that he broke Parliamentary rules. A spokesman said:
The PM is aware. He thinks Patrick Mercer has done the right thing in referring himself to the Parliamentary Commissioner for Standards and resigning the whip. It’s important that the due processes take their course.
Conservative MP Patrick Mercer has announced he is retiring the party whip and will not stand in the next election. In a statement he said he was taking advice over allegations that he has broke Parliamentary rules.
Panorama are planning to broadcast a programme alleging that I have broken Parliamentary rules. I am taking legal advice about these allegations, and I have referred myself to the Parliamentary Commissioner for Standards.
In the meantime, to save my Party embarrassment, I have resigned the Conservative Whip and have so informed Sir George Young. I have also decided not to stand at the next General Election.
Conservative MP Patrick Mercer has resigned the Tory whip following a confrontation with The Daily Telegraph, the newspaper alleges.
The Telegraph say they have been investigating the former shadow minister over "major lobbying" claims.
Conservative MP Patrick Mercer has announced he is resigning the Conservative whip.
Mr Mercer told The Times he did not plan to join UKIP or any other party, and would stand down at the next election, but declined to give a reason for his decision.
Tory MP and former army officer Patrick Mercer has responded to a report stating that the army is wasting £94 million training young recruits, he said the report needed to be examined carefully.
– Patrick Mercer, Member of Parliament for Newark
I commanded 150 Junior Leaders in the 1980s, the majority of whom went on to be first class infantry soldiers.
However, social conditions, financial conditions and recruiting have all changed over the last couple of decades and if it now seems that junior entry soldiers are less than cost effective, the whole issue needs to be looked at.