Former British transport secretary Stephen Byers referred himself to parliament's standards watchdog today after being secretly filmed claiming he could be paid like "a cab for hire" to lobby the government.
Mr Byers told undercover reporters he could be hired for £5,000 a day in exchange for access to ministers, secret government information and advice on influencing policy.
Mr Byers, who steps down as a Labour MP at an election due by June, asked parliament's standards commissioner John Lyon to investigate the allegations published in a Sunday newspaper.
"I am confident that he will confirm that I've complied with the MPs' code of conduct and have fully disclosed my outside interests," he said in a statement.
He later withdrew his comments to the undercover reporters and said he had exaggerated his influence. He could not be reached for further comment.
There was a public outcry last year after details of MPs' expenses claims for everything from bathplugs to pornographic films were stolen and leaked to the newspapers.
Conservative leader David Cameron, whose own party was mired in sleaze allegations in the 1990s, said the government should also investigate the Byers allegations.
"This goes to the heart of the question of the integrity of government," Cameron said. The timing of the inquiry is uncomfortable for Gordon Brown, with Labour trailing in the opinion polls.
Mr Brown's spokesman said there was no need for a separate government inquiry, adding: "Stephen Byers has done the right thing by referring himself to the parliamentary authorities."
Mr Byers, a former law lecturer who also served as chief secretary to the Treasury in Tony Blair's government, made his comments to reporters working for the Sunday Times newspaper and broadcaster Channel 4. Eight MPs leaving parliament this year were approached.
The reporters posed as representatives of a fictitious American communications company, Anderson Perry, that wanted MPs to work on behalf of its corporate clients as lobbyists. Former Labour ministers Patricia Hewitt and Geoff Hoon also offered to help. They denied any wrongdoing.
The allegations revived uncomfortable Conservative memories of the "cash-for-questions" scandal that undermined former prime minister John Major's government.
Conservative MPs were accused in the 1990s of taking money from lobbyists to ask questions in parliament. In an echo of Byers' filmed comments, a lawyer for Harrods owner Mohammed Fayed said a lobbyist had told his client "that you rent an MP like you rent a taxi".
Reuters