British Grand Prix organisers admit they are facing a "nightmare" scenario after heavy rain left thousands of fans stranded, with McLaren's Jenson Button predicting tonight's race could be called off if bad weather persists.
Organisers have also urged fans with public car parking to not come to Silverstone, saying only spectators with pre-booked park-and-ride or in local campsites were advised to attend the qualifying day.
An estimated 80,000 fans were expected at Silverstone for qualifying yesterday, but thousands of cars were stuck all day in queues approaching the Northamptonshire circuit.
Organisers fear that the situation could get worse. Up to 125,000 people are expected on site: about 40,000 of them are staying at campsites around the old airfield and it was their campervans which organisers say were at the heart of the chaos.
"The problem is that the campers are turning up at their campsites, and being turned away because of the ground," said Katie Tyler, Silverstone's head of communications. "The farmers who own the private campsites, along with our own official one, Silverstone Woodlands, are saying, 'We can't take any more, we're going to relocate you'."
McLaren's Lewis Hamilton topped a largely meaningless first day of practice during which Williams's Bruno Senna and Ferrari's Fernando Alonso crashed.
Little valuable data could be gathered ahead of this afternoon's qualifying session.
Button said afterwards that he could not see the race being allowed to go ahead if the rain kept on coming. "You wouldn't want to be racing in those conditions," he said. "There's a lot of standing water. You have to memorise where the rivers are. One of the worst is the Hangar Straight before Stowe at 290km/h, suddenly you cross a river which gives you wheel spin and at that speed it can snap out of control easily. If it is like this in qualifying [the session] will go ahead because it's one car at a time. I don't think we would want to race in those conditions."
It was not only fans who were caught out. Red Bull's Mark Webber sent for a scooter after his helicopter was unable to take off.
Tyler said there was every possibility of more chaos.
"It's a nightmare. If we get more rain we have to be honest about it, it will be slow and there will be problems."
British Grand Prix live, Sky Sport 2, 11.55pm tonight.
- The Independent