Pirelli has confirmed that Sebastian Vettel's tyre failure on the penultimate lap of the British Grand Prix was caused by driving around on an underinflated tyre that was the result of a slow puncture.
Vettel suffered a blow-out on his front-left tyre towards the end of the race at Silverstone, costing him a podium finish.
The incident came one lap after Ferrari team-mate Kimi Raikkonen had also suffered a front-left failure at the same point of the circuit, but Pirelli stressed after the race that the incidents were separate.
In a statement issued on Friday, Pirelli confirmed that after analysing Vettel's damage tyre and the relevant data, it could confirm that a slow puncture was the root cause of the problem.
"Pirelli has concluded the analysis on Sebastian Vettel's damaged front-left P Zero Yellow soft tyre, which affected him two laps from the finish of the British Grand Prix," the statement reads.
"As appeared clear since Sunday afternoon, a full investigation has now confirmed that the original cause of the failure was a slow puncture. The consequent driving back to the pits on an underinflated and then flat tyre led to the final failure.
"Kimi Raikkonen's damaged tyre shows less evidence of what occurred, so further tests and analysis are still ongoing in Pirelli's laboratories and indoor testing facilities.
"It will take a few more days to reach a definitive conclusion."