AN MP who resigned the Conservative whip amid cash-for-questions allegations tabled parliamentary questions on behalf of a lobbying firm that was paying him thousands of pounds, it has been alleged.

Patrick Mercer announced that he resigned the whip to "save my party embarrassment", that he would quit the Commons at the general election, and had referred himself to the Parliamentary Commissioner for Standards.

The former shadow minister said he was taking legal advice after being caught in a sting operation by The Telegraph and the BBC's Panorama programme.

Mercer was reportedly recruited by undercover journalists posing as lobbyists representing businesses seeking to end Fiji's suspension from the Commonwealth and signed a £2000-per-month contract. Fiji was suspended in 2009 over human rights concerns and a lack of democracy.

It is alleged that after being paid £4000, he tabled five related parliamentary questions as well as a parliamentary motion.

A Tory spokesman said Prime Minister David Cameron thought the MP had "done the right thing".

The former army colonel served as shadow homeland security minister until 2007, stepping down after suggesting that racism was "part and parcel" of life in the forces.

Jon Trickett MP, Labour's shadow minister for the Cabinet Office, said: "At a time when faith in politics and politicians is at an all-time low, we must all be working hard to reinstate confidence in elected representatives and the governmental system. Examples such as the allegations are not good for British politics."