The challenge to the Conservative majority on the Committee of Privileges came when all seven Labour MPs 'withdrew' from the investigation into allegations that Tory backbenchers Graham Riddick and David Tredinnick were each prepared to accept pounds 1,000 for tabling questions in the Commons.
The attempt to make the nine Tories on the committee reconsider Tuesday night's vote to hold the first part of the inquiry - into the conduct of the two MPs and the press - in private came after Labour whips advised the Labour MPs to withdraw rather than resign altogether.
Bill Michie, the MP for Sheffield Heeley, set the ball rolling, followed by Doug Hoyle, chairman of the Parliamentary Labour Party, and Alf Morris. By mid-afternoon, the other four Labour members - Tony Benn, Peter Shore, John Morris and Alan Williams - had followed suit.
The high-level committee, which investigates breaches of the laws of Parliament, has always taken its evidence in private. But Mr Morris said there had been 'a welter of sleaze'. It did not help to hold an investigation in secret.
Tory whips insisted they were unmoved by the tactic. 'The issue is whether you want the kind of inquiry that gets at the truth,' one said.
The move came as 61 Labour MPs signed an early day motion calling for full disclosure of the Lord Archer insider-dealing affair, and Paddy Ashdown, the Liberal Democrat leader, called for an Ethics in Public Service Bill to crack down on sleaze and corruption. If the dispute cannot be quickly resolved through the 'usual channels' of negotiation between the Government and Opposition whips, Labour members will not attend the committee, leaving David Alton, Liberal Democrat MP for Mossley Hill, as the sole representative of the opposition parties.
While strongly opposed to the idea of secret hearings, Mr Alton said he believed that 'taking your bat and ball away' at this stage could further damage the reputation of Parliament.
Tony Newton, Leader of the House and the committee's chairman, has pledged that the evidence would be published in full and the report debated by MPs.
Tuesday's first meeting of the committee discussed a compromise position of adopting a presumption that evidence should be taken in public while leaving it open to individual witnesses to request privacy.
The decision was none the less clinched by Mr Newton's casting vote after the other eight Tories insisted on the status quo.
Sir James Spicer, one of the Tory members of the committee, accused Labour of orchestrating a party operation, adding: 'I count many of the Labour members as respected colleagues who could and should be playing their full part.'