LONDON - THE main stadium for the 2012 London Olympics might not be downsized after the games because of England's bid for the football and rugby World Cups, the city mayor said before a new warning about its long-term financial viability.

Mayor Boris Johnson previously said it would be too expensive to keep the stadium at its maximum capacity of 80,000, instead backing plans for a 25,000-seat venue.

But he spoke before London legislators issued a report highlighting how the stadium could become a 'white elephant' due to a lack of regular sports events after 2012. It points out that while the Bird's Nest was the centrepiece of the Beijing Games, it was now largely dependent on tourism as a source of revenue.

With London Olympic organisers unable to find a permanent football club tenant for the stadium after 2012 - due in part to the running track - it is estimated that the 547 million pound ($1.31 billion) development could cost 10 million pounds annually to maintain.

But with England bidding for the World Cup in 2018 or 2022, Mr Johnson hopes the Stratford site could become one of the 16 venues.

Wembley will take centre stage.

Likewise, Twickenham is the English home of rugby union, but the Olympic stadium could also stage matches if the IRB selects England as host of the 2015 Rugby World Cup on July 28. The tournament's rights-holder recommended England's bid on Tuesday.

Arsenal's Emirates Stadium and Tottenham's planned new venue alongside White Hart Lane are also in contention to stage World Cup matches in London. FIFA's executive committee will decide the hosts of the 2018 and 2022 tournaments in December 2010.

Retaining the Stratford site as an 80,000-seat venue received key backing last week from Margaret Ford, who will head the Olympic legacy board in September. Lawmakers in the London Assembly plan to press the mayor on how much it would cost to keep the stadium at 50,000 capacity, if not 80,000.

But the London Development Agency has said the stadium cannot make money or break even after the Olympics and would be subsidized by the rest of east London's Olympic Park. -- AP