By Andrew Benson
F1 staged a demonstration in central London three years ago
Formula One boss Bernie Ecclestone has ruled out staging a London Grand Prix.
Ecclestone said he had spoken to London mayor Ken Livingstone about a race in the capital but said it would be "too expensive" to organise.
Ecclestone also felt it would be very disruptive, adding: "The place would be upside down for six weeks. Nice as it'd be, I didn't think it was possible."
Ecclestone said Livingstone was "very supportive" but the mayor was not able to provide enough financial input.
"He happy to support it up to a point," said Ecclestone. "But the amount they could support it by wouldn't have been anywhere near enough to make it viable."
The mayor was happy to support it up to a point but not anywhere near enough to make it viable
Ecclestone also ruled out the idea of an "Olympic Grand Prix" to tie in with the 2012 Games, which London is hosting.
"I don't know how it could tie in with the Olympics," said Ecclestone. "The Olympics will stand on its own. It won't need any support. Hopefully."
Silverstone is the current home of the British Grand Prix but its contract to host the race runs out after 2009 and a new deal depends on a £25m upgrade of the track's facilities.
If that does not happen, the Grand Prix could lose its place on the F1 calendar.
Ecclestone has frequently criticised the Northamptonshire track for being out of date and wants it to match the standards set by new tracks such as China and Turkey.
The British Racing Drivers' Club, who own Silverstone, are working on a plan to develop the circuit's facilities to ensure it can fulfil Ecclestone's criteria.
"We are the trustees of a national treasure - the British Grand Prix at Silverstone - and we want to sit down with the people who have the power to make it work," said BRDC president and former world champion Damon Hill.
"That means Bernie. But Formula One Management is also the constructors. They all want a British Grand Prix, so let's get out and do it."