Betty Boothroyd, the Speaker, yesterday set in train the inquiry - which is expected to go significantly wider than the specific 'questions for cash' claims - by granting a full emergency debate for this afternoon.
The Committee on Privileges inquiry, which, at the very least, is expected to produce new rules governing the submission of parliamentary questions, will examine reports that two ministerial aides, David Tredinnick and Graham Riddick, were willing to table questions in return for payments of pounds 1,000.
The committee has wide powers to call witnesses and make recommendations, including suspension of MPs from the House - though a reprimand and tough new regulations are widely thought at Westminster to be a more likely outcome if the allegations are upheld.
Mr Riddick and Mr Tredinnick have been suspended as parliamentary private secretaries because of the allegations, made after a Sunday Times reporter, posing as a businessman, approached them.
The Speaker also indicated yesterday that she wanted the inquiry to cover the methods used by the Sunday Times in establishing the willingness of the two men to ask parliamentary questions in return for payment.
The inquiry is also expected to cover MPs with consultancies - which they enter in the members' interests register - and who table questions on behalf of their clients. The Speaker pointedly recalled to a sombre Commons yesterday that the Select Committee on Members' Interests had three years ago stressed there was a 'danger that some Members may make the mistake of believing that correct registration and declaration adequately discharged their public responsibilities in respect of their private interests'.
The committee had gone on to say that a Member must be vigilant that his or her actions do not bring the house into dispute, adding: 'A financial inducement to take a particular course of action in Parliament may constitute a bribe and thus be an offence against the law of Parliament.' According to transcripts of tape-recorded conversations between the two PPSs and a Sunday Times journalist posing as a businessman, both men accepted the offer of a payment of pounds 1,000 in return for asking the questions.
Both have strenuously denied any wrongdoing and support an inquiry. Mr Tredinnick said he 'refused to accept a cheque' and Mr Riddick that he decided at 'an early stage' not to accept payment.
A formal motion being drawn up last night by Nick Brown, acting shadow Leader of the House, will 'call attention to a report in the Sunday Times newspaper on 10 July that members of the House had been offered, and had accepted, payment for tabling of parliamentary questions; and to move that the matter of the complaint together with the issues referred to in the statement by the Speaker on 12 July, be referred to the Committee of Privileges.' Labour will press for a radical tightening of rules covering the widespread and lucrative consultancies enjoyed by MPs.
Joe Ashton, the long-serving Labour MP for Bassetlaw, called in a point of order for the committee to break with precedent and sit in public and for its proceedings to be printed in full.
Privileges committees are normally made up of senior MPs, including Privy Councillors. But Dale Campbell-Savours, the Labour MP for Workington, said that Privy Councillors - the Commons' 'great and good' - who themselves had directorships and consultancies should be excluded from sitting in judgement.
Major's anger, page 2
Parliament, page 6
MPs' Charter, page 14