MPs' doomed attempt to keep their expenses secret cost the taxpayer £170,883 it has been revealed.
The information, which was eventually released last month following a three-year legal battle, showed Tony Blair spent over £6,000 on a new kitchen just as British troops were going to war in Iraq.
The high court eventually ruled in favour of the original decision by the information commissioner.
The Commons paid out £82,673 in legal fees to appeal the decision.
Litigation costs for campaigners appearing in court arguing for disclosure stand at £39,363 - although that is an agreed interim figure.
Finally, a legal bill of £48,847 stands a result of advice offered to other cases connected to MPs expenses, bringing the total to £170,883.
The House of Commons Commission says that figure could rise, however.
The revelation increases the pressure on Michael Martin, whose usually non-controversial role as speaker has come under unprecedented scrutiny throughout the controversy.
Matthew Elliott, chief executive of the Taxpayers' Alliance, said: "It's disgusting that so much taxpayers money has been wasted trying to keep this information secret.
"They are our MPs, it is our parliament, and it is our money. We have a right to see how politicians spend our taxes.
"Michael Martin has behaved arrogantly and disdainfully towards the public whom he is meant to serve. He should have accepted our right to know in the first place and this money could have been saved."