Arguments for and against...

Existing infrastructure: London is served by five airports and has 36,000 three-to five-star hotels, making it one of the few cities in the world capable of coping with the huge influx of visitors.

Legacy: Olympic facilities such as the stadium and athletes' village would be used for decades afterwards. If the Games is in east London the deprived boroughs of Newham, Hackney and Tower Hamlets would be given a considerable boost. After the event the Olympic village would be used as housing.

Investment: If TV rights and International Olympic Committee income stay at current levels the organising committee would get an estimated £1 billion from the IOC. EU funding would also be available particularly if the Games is held in east London, a Category One regeneration area. On top of that, the report by Arup Consultants says the Games could also make a profit of £100 million (although it could also make a loss).

Transport: The Olympics would accelerate improvements in the infrastructure of London transport, such as an extension to the Jubilee Line to serve outlying venues in east London. Organisers intend to maximise the Thames, ferrying spectators in fleets of river boats that would continue after the Games. British Olympic Association chief executive, Simon Clegg, said: "It would provide a unique opportunity for driving forward infrastructure development."

Social effects: Promotion of sport as a social benefit. Crime in Manchester has already dropped significantly since the Commonwealth Games began. The Games would be expected to inspire Londoners to take part in sport long term, leading to a reduction in crime and savings to the health service.

AGAINST...

Cost: At least £2 billion would be needed if London was to win similar plaudits as Sydney. Money would probably have to come both from the Government and private sources. The Arup report says the Games could make a loss of £150m.

Transport: The creaking transport system would be unable to cope with the Olympics. A five-mile car journey can take two hours and the Underground is suffering from years of neglect. Major improvements under the PPP (public private partnership) are not expected for 10 years. Ken Livingstone's plans for charges on the capital's roads could make things worse.