Mr Speaker had a busy time during today's business questions as Labour MPs vented their anger at what one called "Ashcroft-gate".
Harriet Harman brushed off repeated attempts by the chair to steer the session toward the business of the House.
She said the revelations over the tax status of Conservative party donor Lord Ashcroft were "the same old sleaze from the Tories" and "sleaze on a multi-million pound scale",
Lib Dem business manager David Heath got the ball rolling when he called for a debate on the "extraordinary amount of money" spent in marginal constituencies by Lord Ashcroft supporting Tory candidates.
He said the whole issue of how people are appointed to parliament needs to be discussed.
The Speaker warned the House to exercise "considerable care" when making reference to "a member of another place" and told Harman to focus her remarks on the business of the House.
She replied that Lord Ashcroft's tax status is to be investigated by the public administration select committee and so is relevant to business questions.
"I am entitled to put forward my views," Harman said.
She called on William Hague to be "more honest" with the committee than he has previously been over the so-called undertaking given by Lord Ashcroft before he was appointed to the Upper House.
Celia Barlow (Lab, Hove) continued the attacks.
She said her Tory opponent has "boasted" in the local paper that Hove is an "Ashcroft target seat" and called on the government to investigate "so that members in marginal seats can work out how much of the £15m of Latin American money" has been spent in their constituency.
Harman told MPs there is "deep disquiet about the fact that the Conservative party have sacrificed their integrity for money".
She accused the Tories of "trying to buy seats with the Belize dollar".
Sir Peter Tapsell (Con, Louth and Horncastle) said "whatever the strength of views" Harman has a "particular duty to uphold the traditions of House" and should not accuse members of the Lords of offences.
He added that if she made similar statements outside the Commons she could be sued for slander.
Mr Speaker reminded Tapsell that business questions must be used to ask for a debate or a question on a specific issue.
Harman said business questions is also an occasion to discuss what is going on in the Lords and select committees.
She said she was not hiding behind parliamentary privilege as "it is fact" that Lord Ashcroft was only allowed to take his seat in the Lords because he gave assurances about paying tax that he then broke.
Mr Speaker rose to remind the House that criticism of peers "should be on a substantive motion" and it is "reasonable and proper for me now to ask members to focus on the business of the House".
Labour MPs persevered, with David Winnick (Lab, Walsall) asking for all documents about Lord Ashcroft's peerage to be placed in the library of the House.
Harman said she will consider how this issue will be aired in the Commons but it is not a matter for the government to decide who sits in the Lords.
She said assurances were given to then-Tory leader William Hague by Lord Ashcroft.
Barry Gardiner (Lab, Brent North) called for a debate on Bearwood Corporate Services, Lord Ashcroft's company, and on why the tax system "allows company losses to be offset against other tax liabilities".
Harman said she would ask the chancellor to look into the issue, adding that "what we all want to see is maximum transparency".
Richard Caborn (Lab, Sheffield) said there should be an urgent debate on "Ashcroft-gate" as it goes to the heart of democracy and the heart of a party that wants to be the next government.
He said some of his constituents have been in touch to ask how a company can spend £120m and still not pay tax.
Harman replied that "there is clearly a desire in the House to understand what has gone on" and accused the opposition of "eight years of smokescreen" over Lord Ashcroft's tax status.
"This is the same old sleaze from the Tories," she added.
"We are very concered that money that should have gone to pay taxes has instead gone to the Conservative party."
Mr Speaker said amid accusations of sleaze it "would be of benefit to the House if we were to move on" from discussing Lord Ashcroft.
Denis MacShane (Lab, Rotherham) pointed out that ten years ago the former Speaker did allow him to use the phrase "Lord Sleaze of Belize" in reference to Lord Ashcroft and asked if the rules on unparliamentary language had changed.
After Barry Sheerman (Lab, Huddersfield) rose to defend Labour donor Lord Paul, and Harman again stated that Lord Ashcroft "made assurances and did not keep them," Mr Speaker urged MPs to "move on".
Undeterred, Dennis Skinner (Lab, Bolsover) called for debate next week on Lord Ashcroft, who "is not paying taxes and giving money to the Tories".
He claimed the British taxpayer is "bankrolling the Tories" and asked Harman to ensure David Cameron and William Hague are asked what they knew and when.
Mr Speaker told Harman not to answer the question as it was not a business question.
Tony Lloyd (Lab, Manchester Central) said the electoral commission must answer questions about whether Lord Ashcroft's donations are "legitimate legally and morally".
Harman said there will be an opportunity to ask questions about the commission next Thursday.
Julian Lewis (Con, New Forest East) told the House that the electoral commission had just ruled the donations are legal.
Commenting on the commission's report into donations received from Bearwood Corporate Services, a Conservative party spokesman said:
"Following an 18 month investigation, the electoral commission has definitively concluded that donations made by Bearwood, the company in which Lord Ashcroft has an interest, were legal, permissible and correctly reported.
"It has now been put beyond doubt that donations from Bearwood were entirely legitimate.
"Separately, we also know that Lord Ashcroft is non-domiciled, putting him in exactly the same position as Labour and Lib Dem donors such as Lord Paul.
"It is now clear that the continuing attacks on Michael Ashcroft are part of a politically motivated campaign orchestrated by the Labour party in advance of the general election in order to distract attention from the real issues facing this country."
