Kobayashi, who took the #7 TS050 Hybrid he shared with Mike Conway and Stephane Sarrazin to pole position with a record-breaking lap in Thursday qualifying, held a comfortable lead when he stopped on track with a clutch problem during the 10th hour of the race, just after midnight.

It transpired that the clutch had overheated during a safety car period, when Kobayashi had just taken over from Conway and was sat at the end of the pitlane in front a red light waiting for the train of cars formed behind the safety car to pass.

But the Japanese driver started to go when he saw what he believed to be a marshal instructing him to leave the pits, only to be told on the radio to stop again – in the process overwhelming his TS050 Hybrid's clutch and setting up the car's demise on the first racing lap once the safety car withdrew.

"The lead car, the #7, had an extremely surprising problem," Toyota technical boss Pascal Vasselon told Eurosport. "It had been stopped in the safety car queue, [and then] somebody who seemed to be a marshal came to make it start up.

"But the light [at the end of the pitlane] was red, so we stopped it. He started and stopped again two or three times, which was not planned, and it overheated the clutch."

The 'marshal' was later identified to be LMP2 driver Vincent Capillaire, whose Algarve Pro Racing team occupied the final box in the pitlane, close to where Kobayashi was being held.

"On Saturday evening, during the race, I was waiting for my relay, [with my] helmet on the head at my box," said Capillaire in a Facebook statement.

"I wanted to show my encouragement to the lead car, [which was] stopped at [the] red light a few metres in front of my box. It was a spontaneous encouragement. I was fined by Stewards for this gesture, and I admit it was inopportune. I regret that."

LMP2 driver Roman Rusinov, whose #26 G-Drive Racing LMP2 was an early casualty after the Russian driver hit a GTE Porsche, says he understands how Kobayashi would have been confused, having had a similar thing happen to him during qualifying.

"I was in similar situation in qualifying, when I was called for the weighbridge," Rusinov told Motorsport.com. "The whole procedure is like this: you come in, they roll you into the technical zone, then they roll you out and you can go back on the racing track.

"Suddenly I saw a marshal waving me to go, so I just left the technical zone. That was my mistake: you can't go until you are rolled out. They gave me a reprimand.

"It's very hard to understand anything in such situation, because there are a lot of people walking around you, while you're sitting in the car with very limited visibility, talking with your engineer and so on. If a hand shows you 'okay', then you just go."

Rusinov added: "The same was with Kobayashi. When you're in the car – no matter, on track, in your garage or in the pit lane – you use your instincts.

"If you box, there's always a guy who shows you where to go, when to release brakes and where to turn the steering wheel. It's subconscious. You don't need to see this guy, you see only his hand, or even just a glove. It's inside you.

"In this case with Toyota, some guy came near the car and gesticulated. If I was in the car, I would think it's the marshal.

"You have very limited visibility inside the car. That's why if you stay in front of the red light and then a guy shows you that you can go, you do exactly what this guy shows. Maybe the red light is broken, how would you know?"

Speaking to French newspaper L'Equipe, Vasselon added he hoped that Capillaire would apologise to Toyota for potentially costing the team the prize that has eluded it for so long.

"We understood there were no bad intentions in his behaviour, but he did not think about all the consequences of his gesture," said Vasselon.

"I hope at least that he will come to apologise, which for the moment he has not yet done."

Additional reporting by Yaroslav Zagorets and Guillaume Nedelec