The head of the government spending watchdog, who faced calls to resign over his travel expenses, is to retire.
The National Audit Office checks the accounts of Whitehall departments
Sir John Bourn, comptroller and auditor general at the National Audit Office since 1988, will step down in January.
He said it had been a privilege to head up the NAO, but he was stepping down as law changes meant the job would clash with his job regulating auditors.
He was cleared of any wrongdoing in June, after spending £336,000 on 45 trips in three years.
Two weeks ago the Lib Dems described his travel bills of £16,500 spent on trips between April and September, paid for by taxpayers, as "absolutely shocking".
Lib Dem MP John Pugh said he had been anticipating a "difficult meeting" on Monday, when Sir John was due before the public accounts committee to answer questions about the effect of all the "adverse publicity" on the work of the committee.
In a statement, Sir John said it had been "a privilege" to lead the NAO, but his position would clash with his role regulating the auditing profession, under changes in the Companies Act 2006.
He added: "During my term as Comptroller and Auditor General I have seen a profound change in the way government works and the role and influence of public sector auditors.
"Our work now covers topics at the heart of the public debate and our strong focus on improving outcomes leads to lasting improvements."
Lib Dem MP Norman Baker said: "Sir John Bourn has made the correct decision and he should be thanked for the work he has done.
"But the next incumbent cannot end up in a position where he embarrasses the National Audit Office through expenses claims and perceived conflicts of interest."
Sir John's deputy Tim Burr will step up to replace him, until any reforms of the National Audit Office are carried out - it is currently being reviewed by the Public Accounts Commission.
In June the commission ruled that Sir John had acted "in accordance with the existing rules on such expenditure" over his £336,000 bill , run up on 43 foreign trips over three years.
The commission said there was "no evidence of impropriety" in the use of public money, but said a more transparent system was needed.