Speaker spent more than £700,000 on his Commons residence

The Speaker of the Commons, Michael Martin, has been criticised over improvements to his grace and favour flat in the House of Commons, which have cost the taxpayer more than £700,000.

A total of £148,900 was spent on furniture, £191,000 on a new air-conditioning system, £13,000 on art and £291,000 on "building restoration and refurbishment" in Speaker's House.

In total, £724,000 has been spent on the residence – which also includes the State Rooms of the Palace of Westminster – since 2001, according to the figure released under the Freedom of Information rules.

More than £100,000 a year has been spent on average on items including furniture, art and air conditioning for the Grade 1-listed apartments.

The Speaker, who was elected in 2000, chairs a commission which is currently resisting demands for the details of 14 senior politicians, including Prime Minister Gordon Brown and Opposition leader David Cameron, to be disclosed.

Mr Martin's spokeswoman said the spending was part of a rolling programme of improvements which were commissioned by the Parliamentary Estates Directorate.

She stressed that the House included more than just Mr Martin's grace and favour apartment.

She said: "Speaker's House is the official residence of the Speaker.

"Entertainment of visiting heads of state, Parliamentarians and others take place in the State apartments and the costs listed reflect environmental and heritage requirements and health and safety legislation."

The Speaker has already come under fire for claiming more than £75,000 of second homes allowance on his Glasgow property, for which he has no mortgage. His wife has claimed thousands of pounds in expenses for taxis, the disclosure of which led to a row which caused Mr Martin's previous spokesperson, Mike Granatt, to quit.

In the last week, the House of Commons Commission – which the Speaker chairs – has faced criticism from MPs for launching a High Court appeal against the release of a detailed breakdown of MPs' second home claims.

Mr Martin has barred MPs from talking about the legal bid in the Commons.

Mark Wallace, campaign director of the TaxPayers' Alliance, said the disclosure proved that Mr Martin was the wrong person to be heading a review of MPs' expenses.

He said: "These are stupendous sums to spend on just one residence."