RESTRICTIONS on tobacco advertising could threaten Britain's position at the top of international motor sport, according to Lord Hesketh, the president of the British Racing Drivers' Club (BRDC).

Hesketh, speaking at the Autosport International racing car show in Birmingham yesterday, also outlined extensive improvements to Silverstone, the British grand prix venue which is owned by the BRDC.

Referring to Formula One's possible expansion to the Pacific rim area, where restrictions on tobacco advertising are much less rigorous, Hesketh said: "A lot of countries a long way from this island are prepared to spend a lot of money to have a grand prix, and it is important to note that six out of the 12 current Fl teams have tobacco sponsorship which, in itself, is increasingly under threat in Europe.

"In the UK the motor racing industry employs 50,000 highly-motivated people and is a multi-million pound activity, but we want to be aware that there are threats to the whole of the industry from these potential restrictions."

Hesketh, however, reaffirmed the BRDC's determination to keep investing to ensure that Silverstone remains a state-of-the-art venue well into the next century.

For 1997, the grand prix circuit will feature increased speed with safety, thanks to the reshaping of Copse corner, and the complete rebuilding of the three-corner Priory, Brooklands and Luffield loop, much of which has been carried out in consultation with world champion Damon Hill and Martin Brundle.

"The latest changes to Silverstone represent an investment of £4.5 million to add to the £8 million spent over the last three years," said Hesketh. "In the immediate future I do not anticipate any great reduction in the expenditure."

Ironically, Brundle will probably never get the opportunity to tackle the new Silverstone circuit at the wheel of an Fl car. Yesterday he heard formally that his place in the 1997 Jordan/Peugeot team was being taken by the promising young Italian driver Giancarlo Fisichella.

Hill, meanwhile, is intent to enjoy many testing miles this year at Silverstone at the wheel of the new Arrows-Yamaha Al8, which was unveiled at the car show.

Although Hill appreciates that the new car - which carries no tobacco sponsorship - will be very much part of the supporting cast from the start of the season, he and his new team chief, Tom Walkinshaw, believe they area in at the start of something big.

"I am under no illusions," said Hill, "it's going to be a very tough year for me and I don't know when I will see a clear track ahead of me again. It is going to be difficult to predict where we will be placed on the starting grids, because our switch to Bridgestone tyres - which are new to Fl - will tend to shuffle the pack unpredictably.

"The team has done a lot of work enhancing the reliability of the Yamaha engine over the winter, but the real test of the season will be how quickly the team can produce development components and fit them to the car.

"I accept that we will not be winning and that my Williams period is done - that's over. But I believe that with Arrows I have an opportunity to show the other talents which I possess, tackling races in all its forms, developing a team and giving the best possible account of myself on race days."

The next chapter of Hill's career begins next week when he gives the Arrows-Yamaha its first shakedown run at Silverstone, followed by an intensive programme of development at Jerez, in Spain.