LONDON -- Former champion Jackie Stewart has hit back at Formula One chief Bernie Ecclestone and world motorsport head Max Mosley for 'vicious' criticism in a continuing war of words over Silverstone.

The circuit, which hosts Sunday's British Grand Prix, has been regularly slated by Ecclestone -- who last month branded it an embarrassment and the year before as a country fair masquerading as a world event.

	Stewart doesn't understand the continuing criticisms of the Silverstone circuit.

Mosley told BBC radio last week that Silverstone was 'fairly well down the list of circuits worldwide and probably at the bottom of the list in Europe'.

Stewart, chairman of the British Racing Drivers' Club that owns the circuit, told reporters at Goodwood's Festival of Speed at the weekend that he was puzzled by the bosses' continual threats and criticism.

"I just do not understand why they are being so vicious," he said. "If they have an agenda I do not know what it is. What I do know is that it is not a fair and level playing field.

"What Mosley and Ecclestone have been saying about Silverstone has gone out of all proportion and reality.

"Mosley has been quoted as saying he can't guarantee a grand prix at Silverstone beyond 2004 but yet he is still talking about going back to Spa in Belgium and other tracks."

Stewart said Silverstone was better than Brazil's Interlagos, Spa, Hungary and Imola in Italy and accused Ecclestone of milking Formula One of revenues that could help circuits like Silverstone.

"The financial structure of the world championship is completely unbalanced," the Guardian quoted him as saying.

"It is all flowing out of the sport. Ecclestone's group of companies removes the television money, the circuit advertising, the corporate hospitality, even the title sponsorship of the grand prix support races.

"The FIA earned millions when they gave the commercial rights to Formula One to Ecclestone for 100 years.

"None of that money, to my knowledge, has gone back to circuits but Mr. Mosley has nice new offices in Trafalgar Square (London) as well as in Paris and Geneva. And I don't know when he was at Silverstone last."