SAO PAULO, Brazil, Oct 19, 2007 (AFP) - World championship leader Lewis Hamilton received a scare in the countdown to Sunday's title decider in Brazil when falling foul of Formula One's strict tyre regulations in Friday practice.

The British rookie topped the times at the interlagos circuit ahead of his McLaren team-mate defending title-holder Fernando Alonso after Friday's opening practice sessions.

When the session ended he was interviewed by FIA officials concerning the inadvertently illegal use of two sets of wet tyres for the morning session.

But after several hours the race stewards elected to give Hamilton and McLaren what was in effect a slap on the wrists rather than a harsher penalty.

McLaren were fined 15,000 and Hamilton restricted to using one set of rain tyres.

McLaren team chief Ron Dennis admitted the mistake was made by the team.

He said: "Despite topping the timesheets, today has not been perfect for us as we made a mistake in this morning's session and used one set of tyres too many on Lewis's car. This was unfortunate and clearly did not provide any
advantage."

He added: "It was 100 percent the team's mistake. Lewis did an installation lap on one set of wet tyres, and we just put on another set. It was 100 percent our fault.

"He only did an in-and-out lap, so there was no advantage, but it was clearly a breach of the rules. Two other people made the same mistake, and it is up to the stewards to decide on the penalty.

"We are trying maybe too hard, and it was a silly mistake. We can do no more than our best, and we are really trying hard. People make mistakes. I am not trivializing it.

"It just perhaps shows we are all human. I don't think anyone will imagine there was any advantage there at all. There is a rule there, we broke it, and we just have to get on with it."

Hamilton went to see the stewards and left grim-faced, but the loss of a set of tyres may not be a great setback if a weather forecast predicting dry weather on Sunday proves to be accurate.

He was not deeply upset by his general work for the day and said: "Finally, I enjoyed getting out on this amazing track, but it was just a shame that the conditions were not great this morning.

"We couldn't really do as much running as we would have preferred. However, it was good to get a feel for the track, and we made reasonable progress on the set-up work and tyre comparison despite the cold conditions."

His McLaren team-mate Fernando Alonso said: "The session this afternoon was far better than this morning. We did not expect it to stay wet for the rest of the weekend so took the decision not to do any running in the morning, as we wouldn't achieve any conclusive results on set-up and tyre comparison work.

"Also there is a new track surface here and as a result it was very slippery. However by this afternoon the track had dried out, and it was clear that the conditions were improving. I am looking forward to a competitive weekend."

Finn Kimi Raikkonen, the third driver with a chance of lifting the title, was fourth in the practice timings.

He said it had been a puzzling day, as usual, for a Friday because a combination of the morning's wet weather and then traffic problems in the afternoon had stopped him from showing his best.

"We will see more tomorrow of what is really going on," he said.

Hamilton leads Alonso by four points going into Sunday's showdown in which Raikkonen can also clinch the title for Ferrari if he wins the race and the two McLaren men fail to score sufficient points to take the title.

Hamilton shrugged off the tyre controversy to clock a fastest time of one minute and 12.767 seconds on his first day appearance at the famous old Interlagos circuit to finish 0.122 seconds ahead of Spaniard Alonso, 26.

Raikkonen was fourth in practice, one place behind his Ferrari team-mate local hero Felipe Massa of Brazil who won last year's race.

Aside from Hamilton two other drivers to fall foul of the new tyre regulations were Briton Jenson Button of Honda and Japanese Takuma Sato of Super Aguri. These last two received the same punishment.

Article 25.3 of the F1 Sporting Regulations states: "No driver may use more than one set of wet and one set of extreme weather tyres during P1 and P2."

The issue was brought to the race stewards' attention by FIA technical delegate Jo Bauer.