Prince Andrew flew to a golf tournament on a nearly $A29,000 (NZ$31,266) taxpayer-funded private jet.
Palace sources say there was no other way for the Duke of York to make the trip last July, according to The Sun.
"Airmiles Andy" boarded a private jet from Farnborough, Hampshire, to The Open Championship in Portrush in Northern Ireland, although there are 13 daily flights from London to Belfast.
The golf club cut ties with former patron Andrew amid the Jeffrey Epstein scandal after his disastrous BBC interview.
"There was no other way for Andrew to make the trip," a palace source claimed.