The head of the government's spending watchdog must quit after running up an "absolutely shocking" bill for recent foreign travel, the Lib Dems have said.
The National Audit Office checks the accounts of Whitehall departments
Sir John Bourn stayed in five overseas countries at a cost of £16,500, taking his wife - whose bills were also met by taxpayers - on three of those visits.
Between April and September, Sir John also spent £1,650 on 11 business meals.
His "gigantic bills for largesse" were "incredible", said Norman Baker, the Lib Dem Cabinet Office spokesman.
"The time has come for him to call it a day in the interests of good administration."
'First class travel'
In June, Sir John - the comptroller and auditor general at the National Audit Office since 1988 - was cleared of any wrongdoing after spending £336,000 on 45 journeys in a three-year period.
SIR JOHN BOURN'S RECENT TRIPS
£8,593* - San Francisco
£2,723 - Kazakhstan
£2,217* - Lisbon
£1,718* - Venice
£1,290 - Moldova
£455 - Belfast
* accompanied by Lady Bourn
Source: National Audit Office
Lady Bourn had gone with him on 24 of those occasions, which cost taxpayers £76,000.
The Public Accounts Commission investigated him and found "no evidence of impropriety", but did call for "a more transparent system" in processing Sir John's expenses.
It noted Sir John travelled "first class for rail travel, business class for short-haul flights and first class for long-haul flights".
And it said Lady Bourn went with him "on visits where the host would have reasonable expectations she would attend".
The latest figures, covering the period from April to September 2007, follow the National Audit Office's decision to publish details of travel and subsistence costs incurred by senior staff every six months from now on.
Sir John spent five days in San Francisco in April, at a meeting of the Global Working Group of Auditors General.
The air fare for him and his wife, Lady Bourne, was £7,730, with accommodation costing a further £781.
Ten days later, the couple went to Venice, where a Financial Services Authority conference was being held. Their travel bill was £1,718.
And a fortnight after that, a seminar saw both flying to Lisbon at a cost of £1,715, plus £400 for accommodation.
Sir John also paid £2,107 to go to Kazakhstan and £1,117 on a trip to Moldova, both in September, and signed a "memorandum of understanding" on each occasion.
In addition to these trips, a return flight to Belfast in June cost £329.
His £1,651 bill for hospitality covered meetings with parliamentarians, senior government officials and clients of his department at five-star London hotels and upmarket restaurants.
Mr Baker said he was also angry about a visit to the British Grand Prix, "paid for by BAE Systems", the defence firm under investigation by the US Justice Department over allegations it ran a fund to help it win orders from Saudi Arabia for aircraft and military equipment.
This "compromises the independent and professional standing essential to someone in this post", Mr Baker said.
His Lib Dem colleague Norman Lamb said there was a great deal of scrutiny on MPs' spending, and "the focus should also be on the person who, ultimately, takes an overview of public expenditure and ensuring money is spent wisely".
"I just do not see that he can continue in this role given what we now know," he told the BBC News website.