The publication today of the details of MPs' expenses will make uncomfortable reading for the Westminster officials who signed off hundreds of lavish claims.
Backbenchers from all parties say that they were encouraged by the Commons Fees Office to maximise their allowances and were given poor advice on the admissibility of claims.
The expenses storm has left a question mark over the office, now the Department of Resources, and its director general, Andrew Walker.
Gordon Brown has announced plans to move responsibility for MPs' pay and allowances from the Commons to an independent regulator. Ben Chapman, the Labour MP for Wirral South, who is retiring at the next election over his "phantom mortgage" claims, has received an apology from it for its "incorrect advice".
He has circulated the letter to other Labour backbenchers, telling them: "As many of us are still in the process of seeking clarifications and corrections from the Fees Office, some may find my experience useful in your future dealings with them."
The Commons authorities also cleared a £22,500 claim from Margaret Moran, the Luton South MP, to treat dry rot in her second home. She had to step down over the issue, saying: "The House of Commons Fees Office gave me incorrect advice upon which I acted. They have now apologised."