Prime Minister Gordon Brown and senior politicians rallied round House of Commons Speaker Michael Martin on Monday after he was criticised over his use of parliamentary allowances.

"As far as his work as speaker is concerned, I think most people know that Michael Martin has been and is a very very good speaker," Brown told Five News in an interview.

"He obviously brings a huge amount of experience from things that he's done earlier in his life to the job, and I think there's enormous respect for what he's achieved as speaker."

Martin, a former metal worker and union official, said he would not step aside.

"This House has charged me with a responsibility and I will carry out that duty until this House decides otherwise - and that is a good thing for the reputation of this House," he said in parliament.

Newspapers and political commentators said Martin should be beyond reproach and should go, after a weekend of negative headlines following the resignation of his press spokesman.

Mike Grannatt said he had quit because he had been misled over 4,000 pounds of taxi expenses run up by Martin's wife.

Grannatt had briefed reporters that a Commons official had accompanied Mrs Martin on all the trips while shopping for receptions and banquets, but he resigned after it emerged that this had not always been the case.

Newspapers also criticised the speaker for claiming more than 75,000 pounds over the past six years for the costs of his constituency home in Glasgow, which is not mortgaged.

In addition, there have been complaints about Martin's use of air miles earned on official business to pay for flights for his family.

John Spellar, head of a parliamentary panel conducting a review of MPs' expenses, told BBC radio that Martin was the victim of a disgraceful campaign by newspaper "snobs".

"Michael is proud of his roots, he started off as a sheet metal worker, he's come up through the trade unions - all the things that those snobs in the press gallery absolutely hate."

He said despite the press coverage, nobody had said the speaker had actually broken parliamentary rules.

"Nobody would expect him to," said Spellar. "He's an absolutely honourable and decent man."

Liberal Democrat Leader Nick Clegg told BBC television Martin was being subjected to a "witch hunt".

Health Secretary Alan Johnson told GMTV he supported the speaker and expected the row would blow over.

By tradition, the speaker cannot be sacked. But former independent MP Martin Bell, elected in 1997 as an anti-sleaze candidate, told BBC radio Martin should seize the initiative and resign.

"I think he should take soundings this week and announce his departure after the Easter break."