House of Commons Speaker Michael Martin has come under fire after it emerged he spent more than £20,000 of taxpayers' money on lawyers to challenge negative press stories.
He was accused of treating the public with contempt after running up the bill - to be paid out of public funds - with City libel law firm Carter-Ruck.
The firm was retained to represent Speaker Martin following a string of unflattering newspaper articles questioning his impartiality and conduct.
It emerged today that the total bill for the firm's services during June, July and August was £21,516.
Liberal Democrat MP Norman Baker expressed alarm at the size of the bill and the willingness of the Commons authorities to approve the expenditure.
"This is a deeply worrying figure," he said.
"Of course it's right that there should be legal advice available to all members of the House of Commons.
"But in this case it appears the very expensive Carter-Ruck has effectively been used to issue press releases and that those instructing them have been content to sign blank cheques irrespective of the cost to the taxpayer."
The TaxPayers' Alliance accused the Speaker of treating the public with contempt and adopting "the airs and graces of the ancien regime".
Chief executive Matthew Elliott said: "By using our money to hire the best media law firm in the land to defend himself against his critics and to soothe his thin skin, he is showing contempt towards taxpayers.
"If he wants to hire flunkies, he should pay for them himself and not expect us to pick up the tab.
"He should not forget how far £21,000 could go to help taxpayers in his home town of Glasgow."
Speaker Martin, famed for his background as a working-class Glaswegian and former sheet metal worker, now earns £136,677 a year for presiding over debates in the Commons.
But he has come in for repeated criticism for his rulings and the exemption of his wife, Mary, from security checks in the Palace of Westminster, where they live.
The House of Commons Commission, which is chaired by Speaker Martin and oversees parliamentary business affairs, spent £17,300 on an unsuccessful attempt to block the FOI request.
Nick Harvey, the MPs' representative on the Commission, has now disclosed the additional bills for Carter-Ruck's services over the summer.
"During July and August, the House administration endorsed the Speaker's use of the firm Carter-Ruck to counteract a series of articles that were published in the media which questioned the impartiality of the Speaker in his official role," he said in a Commons written statement.
"The cost of this advice was £18,696.06."
A spokesman for Speaker Martin confirmed that the money would come from public funds, as would an earlier £2,820 bill for work conducted in June.
He declined to comment further.