The NAO's second-in-command has come under fire after a leading MP questioned the necessity of a trip to Mongolia.
Tim Burr's flights and hotel room for the 2006 trip were paid for by the taxpayer, sparking outrage in Westminster.
Liberal Democrat MP Norman Baker told the Mail On Sunday: 'It is not clear how the British national interest was served by sending Mr Burr to the Mongolian National Audit Office. It is even less clear how his wife's presence would help.'
Burr was also accompanied by his wife Gillian, but her accommodation and travel was paid for out of her own pocket, the NAO said.
Burr will become acting comptroller and auditor general when Sir John Bourn steps down at the end of the month.
Baker added: 'The cavalier use of public money to visit far-flung corners is endemic in the body that is supposed to regulate government finances.'
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