Speaker Martin clings on for his £100,000 pay-off

There are 100,000 reasons why MPs should not allow Michael Martin to remain as Speaker of the House of Commons after his statement today - for 'Gorbals Mick' stands to receive a £100,000 golden handshake if he remains in his job until the general election.

Which is why, as predicted by the Mole, he is clinging to his chair like a limpet rather than become the first Speaker since the 17th century to be forced out.

He will plead to keep his job today, with a promise to retire at the next general election and in the meantime oversee the reform of Commons expenses and allowances.

But today's revelation in the Daily Telegraph has hardened opinion against him and suggests he is the last man on earth to be put in charge of the clean-up.

Martin has presided over the abuse of expenses and the cover-up to prevent the public finding out about it. He fought tooth and nail as chairman of the Commons Commission to stop the details of MPs' expenses being revealed under the Freedom of Information Act. And when the lid was lifted, he called for the police to be brought in to track down the whistleblower who sold the disk containing the data to the Daily Telegraph, believed to be for £75,000.

Now we have the very serious claim in today's Daily Telegraph that the House authorities colluded with various MPs to allow them to over-claim for mortgage interest payments.

We have only one name so far - that of Ben Chapman, a Labour MP, who admitted last night that he was allowed to continue claiming for interest payments on his entire mortgage after repaying £295,000 of the loan in 2002.

It was Martin who, as head of the House authorities since 2000, was in charge of the fees office that came to this fraudulent arrangement.

Martin could try to blame the phantom mortgage scam on a few rogue officials, but it would not have the ring of truth. John Stonborough, his former spokesman, revealed in the Sunday Times that Martin bullied staff who raised objections to some of the practices. He "reacted violently" when it was suggested to him that his practice of claiming a second home allowance on his house in Glasgow "did not look good" when he had a grace and favour home in the Commons.

Also, it was Martin who personally edited the 2004 'Green Book' governing how MPs could claim allowances - thus missing an opportunity to reform it.

The clamour for Martin to go immediately has increased over the weekend and will grow louder today because of the Telegraph's latest revelation. The problem for Gordon Brown is that the Speaker's departure would mean a by-election in Martin's Glasgow constituency - with the high risk of another embarrassing victory for the SNP.

But the motion of no confidence in the Speaker, tabled by Tory MP Douglas Carswell, is gaining support. Charles Clarke, the former Home Secretary, is the latest big name to sign. MPs have a right to push their motion to a vote, and the public appear so angry they will not understand or forgive them if they do not do so today.