A new take on Heidfeld's Renault explosion

One of the more extraordinary moments of the Hungarian Grand Prix was the fire and subsequent explosion on Nick Heidfeld's Renault following his pit stop.

This was the second fire for the German this year. He had just made a stop in which he was delayed and the sidepods caught fire.

"In his second pit stop we had a problem with one of the wheel nuts meaning that the car was sat at high revs for a long time, " explained LRGP chief race engineer Alan Permane. "This meant a build-up of heat which caused a fire. Although it looked spectacular it was only a small part of bodywork which burnt on the left-hand sidepod."

This video, shot by a spectator, shows the incident far more clearly than the race pictures.

Renault have not mentioned the explosion in any official communications, nor said what caused it. Paddock speculation was that it could have been a KERS battery, but Renault have said "no 100%" to this today. They are carrying out an internal investigation.

Engineers say that the high pressure air system is also housed around there and there are other high pressure hoses which would blow the side of the car out if the pressure was released quickly.

It makes uncomfortable watching from the point of view of the fire marshal, who is hit by some debris from the explosion. This may well prompt a review of packaging to avoid a repeat of the incident.