Following years of criticism and question marks over its future in the top flight, Silverstone has once again been blasted as Formula 1's worst circuit by the most powerful man in the sport.

Bernie Ecclestone cast further doubt on the British Grand Prix's future on the F1 calendar, with Silverstone's contract up for renewal in 2009 and a ?25 million British Racing Drivers' Club-approved redevelopment programme in the pipeline. He insisted the government should step in to take some of the burden.

"Britain is supposed to be the heart of Formula 1 racing," the BBC quotes the 77-year-old as saying, "and our circuit is bottom of the list. They know exactly what they have to do; they've known for at least five years.

"It's not for us to say where the money comes from, but it's strange because most of the events we have now are supported by governments. With a tiny percentage of what the government are wasting on the Olympics, they could support Silverstone."

Speaking at the launch of the official season review DVD, the sport's supremo went on to express his disappointment that no more movement had been made on the proposal to stage an F1 race around the streets of London.

"Mayor Ken Livingstone was very helpful and we laid a plan out of what we could do," he said. "It would have happened - it was just a question of where the money was going to come from.

"It would cost a small amount compared to what they're spending on the Olympics. If they look at it from a pure business point-of-view - all the revenue it would bring in - I just don't understand why it isn't happening."