The Games could bring a £3 billion boost to the UK tourist industry, according to a review of data from previous Olympic host cities including Seoul (1988), Barcelona (1992), Sydney (2000) and Athens (2004).

But the overwhelming majority of the benefits are likely to be confined to London, according to Travelodge, the hotel group that commissioned the study.

The firm estimates that no more than 10 per cent of the benefits will "trickle down" to the rest of the UK, leaving other parts of Britain for a slice of around £300 million in extra revenues.

The report was carried out by Kurt Janson, an independent tourism expert based in London.

Despite concluding there could be benefits from the Games, he found this was not certain, and proper planning was needed. In Athens in 2004, for example, tourism grew less than the global average because promotion was a failure.

Grant Hearn, Travelodge's chief executive, said: "A tourism legacy requires detailed early planning, world-class airports, attractions, hotels and the creative promotion of the British brand - all of which require serious investment."

The best example of regions sharing in the Olympic dividend was in Australia.

 

After the 2000 Games in Sydney, the surrounding state, New South Wales, saw a significant increase in tourism.

Mark Hutcheon, a spokesman for Travelodge, said: "The evidence from the report is that the tourism benefit from an Olympic Games host city does not automatically extend to the rest of the country.

 

"Barcelona benefited the area around the city but not necessarily everywhere else in Spain. Atlanta boosted Georgia but not necessarily the rest of the south-east United States.

"There is no reason why tourism around the whole of the UK shouldn't be boosted by the 2012 Olympics but this won't happen unless Governments and tourism agencies intervene to provide the right marketing."

He added: "What must be at the top of the devolved administrations' agenda is how they can get a slice of the pie - the Games could be a great gateway to the rest of the UK, but everywhere outside London will have to fight to benefit."