Pirelli tyre problems plague British Grand Prix
Amid growing concerns about the safety of Formula One tires, the sport's governing body has ordered tyre supplier Pirelli to attend a meeting on Wednesday in response to dramatic tyre blowouts that hit four cars at the British Grand Prix.
Lewis Hamilton was leading the race when the rear left tyre on his Mercedes exploded.
There were further blowouts on the rear left tyres for Ferrari's Felipe Massa, McLaren's Sergio Perez and Toro Rosso's Jean-Eric Vergne, whose problems resulted in huge strips of rubber flying across the track and several drivers behind him being hit with debris.
It brought on the safety car, the first of two in the 52-lap race eventually won by Hamilton's teammate Nico Rosberg.
Sauber's Esteban Gutierrez needed a replacement for his front left tyre, while Perez had also been hit by a blowout on Saturday.
Pirelli has now been summoned to attend a meeting in Germany - ahead of next week's grand prix at the Nurburgring - that was scheduled to involve only the ruling FIA and the sporting directors of F1 teams.
Pirelli could not say what caused the tyre blowouts.
"There have been obviously some issues with rear-left failures which we have not seen before," Pirelli's MotorSport Director Paul Hembery said. "We are taking the situation very seriously and we are currently investigating all tyres to determine the cause as soon as possible ahead of the next grand prix in Germany."
Before he dropped out of the race with mechanical problems, Red Bull's Sebastian Vettel was told over the radio it was unclear if the problems were linked to Pirelli or the curbs at Silverstone.
They later cautioned him and team mate Mark Webber to be careful of the curbs and to watch their rear tyres.
The tyre trouble at Silverstone is only the latest controversy to hit Pirelli, which has come under fire over concerns its tyres are wearing down too quickly and leading to races being disrupted by too many pit stops.
F1 boss Bernie Ecclestone has defended Pirelli, insisting the new tyres are making the races more exciting.
Pirelli and Mercedes were, meanwhile, reprimanded earlier this month by the FIA after being found guilty of conducting an in-season test on the tyres.
After last night's (NZ time) events, several teams and drivers warned of the possible dangers and demanded that something be done by the German Grand Prix.
"Without that tyre problem, I could have made it to the podium because today I had a good feeling with the car," Ferrari's Felipe Massa said, adding he had similar problems with tyres twice in Bahrain.
"Now, our greatest concern revolves around safety," he said. "Even if I can't really tell what happened today, it's unacceptable having to drive knowing you are not safe. Even if, luckily, nothing serious happened, what we saw is very dangerous."
McLaren's Martin Whitmarsh, who heads the F1 teams' association, agreed.
"We had five tyre failures here. Lots of people have a lot of theories about what that is, whether it is fatigue failure or puncture caused by debris," said McLaren's Martin Whitmarsh, who heads the F1 teams' association.
"In fairness, we have to work with Pirelli. We have to support them through this but we have to do something," he said. "I don't think now Formula One couldn't possibly not respond to events this weekend ... We have been lucky that no one has been hurt."
Former F1 world champion Damon Hill, who was at the race, said the tyre issue had to be addressed
"The drivers are clearly not happy and they have a right to be concerned about their safety and everyone's around them," he said
"Silverstone is one of the higher speed circuits we go to. We cannot have doubts about tires when you go to places like this or Spa. The question of whether it's cuts in the tyres, punctures or curbs is not relevant. This is not that different to most of the circuits. In any case, they have to produce a tyre that can cope with all the circuits they visit."
Whitmarsh suggested going back to the 2012 tyres while three-time F1 champion Jackie Stewart said the FIA should lift the ban on in-season testing immediately so that all teams can test their tires this week.
He went even further, suggesting the time may have come for eliminating pit stops altogether and introducing a tyre that can last an entire race - rather than the current situation that requires two or even three stops.
"We don't need to have pit stops to make motor racing exciting," Stewart said.
"We can have tyres that will do the full distance in order to get the safety element in place. If we have to make stiffer tires, a heavy tyre, a bigger tire, let's do that and have no pit stops if that is what it takes to get over this hurdle.
"If we went into another grand prix or two and saw this happening again and something really nasty were to happen, we would never forgive ourselves for not doing something."