Formula One is beset by anger and grief as it struggles to understand the circumstances that left Jules Bianchi fighting for his life following Sunday’s Japanese Grand Prix.

On a tragic day for motor racing in which former F1 driver Italian Andrea de Cesaris was killed in a motorcycle accident in Rome, 25-year-old Frenchman Bianchi suffered severe head injuries when his Marussia car collided with a heavy crane-carrying recovery vehicle.

His accident came in the closing laps of a race won by championship leader Lewis Hamilton of Mercedes and shortly after Adrian Sutil had crashed his Sauber car at the same place just ahead of the Degner turn.

Bianchi was extricated from his car and after examination at the circuit medical centre he was transferred to the Mie General Hospital, about 10 kilometres away.

He underwent surgery and was later described as being in a critical condition in intensive care.

Reports in France that he was breathing on his own, without medical aid, were unconfirmed as other drivers, including Sutil, pointed to the poor light as a factor in the accident.

Many paddock observers also suggested that the race should have started much earlier in the day than 1500 local time to avoid the torrential rain that hit the event ahead of the arrival in southern Japan of Typhoon Phanfone.

Sutil, who had climbed unhurt from his crashed car, stood and watched as Bianchi went off.

“It was quite difficult. In the end, we got more rain and it was dark so visibility was getting less and less and this corner was a tricky one, the whole way through,” Sutil said.

“In the end, when it got dark, you couldn’t see where the wet patches were and that is why I lost the car and it really surprised me. His crash was the same as mine and he had aquaplaning, but just one lap later.”

Williams team performance chief Rob Smedley said: “I would say, in the 15 years I’ve been involved in Formula One, that that was the darkest I’ve ever seen a race event.”

The race started and finished – prematurely when it was red-flagged to stop following Bianchi’s accident – in treacherous conditions with torrential rain and reduced visibility.

But despite that, most drivers said the conditions were not extraordinarily bad and suggested Bianchi had been unlucky.

Williams driver Finn Valtteri Bottas, who finished sixth, said: “The whole race was tough, especially the beginning and end … I think there have been more difficult track conditions than this.

“It’s just a difficult track in the wet. Until then, there was nothing special happening. I think it was just a really, really unlucky situation.”

Compatriot Kimi Raikkonen of Ferrari agreed. He said: “Was it safe? Is it safe ever? You cannot say. Sometimes it doesn’t matter.

“At the beginning of the race, behind the Safety Car, we drive 100 kph and you could aquaplane. So, even if you slow down, you might get into trouble.

“If there’s too much water you can go off. It’s as simple as that.”

Hamilton said: “They (conditions) weren’t really that bad. I’ve had much worse races in terms of aquaplaning.”