Boris Johnson arrived in Beijing today looking tired and dishevelled after a cattleclass flight from London.

British Airways denied the Mayor an upgrade from his economy seat on the nine-hour overnight flight to the Olympics.

City Hall aides are understood to have requested a move to business class for the Mayor before leaving Heathrow but were turned down. A spokesman for British Airways refused to comment on the request or reveal whether the flight had been full.

But the incident is certain to be viewed as a snub by mayoral aides who were convinced their boss would be treated like a VIP.

It is not Mr Johnson's first confrontation with airport authorities - his luggage was delayed at Gatwick earlier this month. He then complained managers had a "chimpanzee-like " control over baggage handlers and that the service was worse than many third world countries.

This time, the Mayor made a high-profile decision to travel economy in a bid to slash costs for the trip funded by London taxpayers. His predecessor, Ken Livingstone, had been planning to travel business class and there was a general expectation Mr Johnson would be upgraded.

He also reduced the size of his party to 13 and cut the amount of time in Beijing from three weeks to five days. The trip is now expected to cost around £167,000.

A source on the plane said fellow economy class passengers were surprised to see such a well-known politician in their midst.

If he had travelled Club World, BA's business class, Mr Johnson would have had a fully reclining seat-bed, 73 inches of legroom and on-demand meals.

Instead, he had to put up with just 38 inches of legroom, and meals and snacks when the cabin crew distributed them.

He was unlikely to have got much sleep ahead of the visit, which kicked off with a meeting with Beijing Mayor Guo Jinlong, who asked him about his flight.

A bleary-eyed Mr Johnson received VIP treatment once he landed at Beijing Capital International Airport and was whisked away in an official car to his hotel.

He had promised to cancel expensive hotel suites booked by Mr Livingstone and downgrade to a cheaper hotel.

But the Mayor and his team are staying in the official International Olympics Committee hotel, the five-star Beijing Raffles Hotel, where rooms start at £400 a night.

A spokesman for the Mayor said: "We were told it would be easier for us to stay at the IOC hotel for security reasons and also because that's where we'll be having meetings with [IOC chief] Jacques Rogge and Seb Coe about the handover to London."

Mr Johnson will have a key role to play in the closing ceremony on Sunday when he receives the Olympic flag from his Beijing counterpart before an estimated worldwide television audience of 1.5 billion.

He is also battling Gordon Brown for the best photo opportunities in the city. The Prime Minister will also be at the closing ceremony and is said to be redrawing his schedule to meet Britain's athletic heroes, including fellow Scot and triple gold medallist Chris Hoy.

The Mayor will welcome budding competitors to the London Games at the Beijing athletes' village.