Some people went by train from London for £14 return. Others drove there and back by car for under £25. But when the Duke of York went to the Farnborough International Airshow last week, he spent £6,000 of taxpayers' money hiring a helicopter.

The Duke - nicknamed Airmiles Andy for his excessive use of expensive chartered aircraft - left Kensington Palace in the French-built Twin Squirrel helicopter at 9.30am
and landed at Farnborough after a 15-minute flight.

Just over four hours later, he flew back to Kensington, despite a spokesman admitting that he did not have any engagements scheduled for that afternoon.

High flier: Andrew arrives at Farnborough after his 17-mile flight in 2006

The Prince went to Farnborough in his role as representative for UK Trade and Investment (UKTI), a Government-funded agency that promotes British trade abroad.

A source close to Andrew said he needed the helicopter to arrive on time for a series of meetings starting at 10am crucial to sealing major contracts between the United Arab Emirates airline Etihad and aircraft manufacturers Boeing and Airbus, which meant hundreds of jobs for British workers.

He added that the Prince, who was travelling with his private secretary and a small security team, was able to add two more meetings to his schedule because of his timely arrival - estimated by industry experts to have cost taxpayers £6,000 for the round trip.

The source said: 'You can have a cut-price Royal Family who go around by easyJet and in the back of a Morris Minor if you want, but there are certain modes of transport
deemed acceptable by the Department for Transport.'

But Liberal Democrat MP Norman Baker said the Prince's spending had become profligate - and was setting a poor environmental example.

He added: 'Lots of people have lots of meetings but they don't need helicopters to get them there. It seems there is no cheque Prince Andrew will not present to the public purse. He shows a complete disregard for taxpayers' money.'

A Buckingham Palace spokesman said: 'It's well known there is often significant congestion round the Farnborough Airshow, and travel by road from Central London could not have guaranteed that the Duke would have made it to his nine meetings.'

But there were no unusual traffic problems in the area on Tuesday beyond the usual congestion expected around the show.

Accounts reveal that the Royal Family spent £4.8million from the public purse last year on chartering helicopters and planes.

Prince Andrew's travel bill for 2007/08 came to £779,469, including £212,880 on travel to Singapore, India and Indonesia in March as a representative for UKTI.

In 2006, he was criticised for using a helicopter for a 17-mile journey from Windsor to the Farnborough show.

In 2005 it was revealed he had spent £32,000 in one year using the RAF to fly him to St Andrews for golf meetings.

Royal aides told the inquiry that he refused to travel by train because he considered it too unreliable.