Spa-Francorshamps: The halo, a sporting innovation that was once almost thrown out on aesthetic grounds, might just have saved a Formula One driver’s life.

Charles Leclerc accepted that he was “lucky” to escape unscathed from a horrifying first-corner crash at the Belgian Grand Prix, as Fernando Alonso’s McLaren was pitched straight over the top of his Sauber after a reckless shunt from behind by Nico Hulkenberg.

One glance at the wreckage of Leclerc’s car, whose halo was disfigured by Alonso’s tyre marks but remained intact, confirmed how fortunate the Monegasque driver had been to avoid serious injury.

Even when the halo was introduced to F1 at the start of this season, there was fervid debate about whether it represented an over-reaction that would dilute the sport’s inherent danger.

The mayhem that unfolded in Spa yesterday, with one side of Alonso’s car reduced to scrap metal and Leclerc protected only by the slender roll-bar around his head, put paid to those concerns for good.

“It could have been very nasty,” said Toto Wolff, the Mercedes team principal. “I’m happy that we have the halo.”

Leclerc’s mother, Pascale, was so alarmed by the TV footage that she had to be sent a picture by his physiotherapist to illustrate that he was unhurt. At a Spa circuit renowned for dramatic starts, as the field jostle for position on the short run down to La Source, this was an incident that leapt straight into the canon of chaos. But unlike in 1998, when the rain magnified the risk, this moment of havoc took place under a clear blue sky.

A piece of carelessly late braking by Hulkenberg was all it look for his Renault to barrel into the back of Alonso, pinballing the McLaren into Leclerc’s path.

“Definitely the halo helped,” Leclerc said. “I don’t know how it would have ended up without it.”

The blameless Alonso, likewise, lauded the device’s effectiveness in this situation. “It was good proof,” the Spaniard said. “We didn’t have any doubts, but in these kinds of -accidents we know that the halo is always a good protection.”

Nico Rosberg, the 2016 world champion, argued: “We can end the halo discussion now. It will save lives.”

For all that the halo has aroused controversy, the intentions behind it were always noble. Since Ayrton Senna’s death in 1994, drivers in many of the higher echelons have been vulnerable, to an unacceptable degree, to head trauma.

Henry Surtees, the son of former world champion John Surtees, was killed in a Formula Two race nine years ago, when his head was struck by a flying wheel.

In 2013, Maria de Villota died from a neurological injury that she sustained in a crash with a lorry during testing for Marussia the previous year. One of Leclerc’s closest friends, Jules Bianchi, suffered a fatal brain injury when his car became wedged under a truck at Suzuka in 2014. So catastrophic was that impact, though, that there is doubt about how much the halo could have done to save him.

In Leclerc’s case, it performed its function to perfection. After a wave of gripes that it would fundamentally harm the sanctity of F1, it proved its value here by coming between a 20-year-old driver and a potentially horrific outcome.

Charlie Whiting, race director for the governing body, the FIA, said: “It doesn’t take much imagination to think that the tyre marks could actually have been on Charles’s head. It would have been a bit of a miracle if they weren’t, had the halo not been there.”

Alonso reacted furiously to Hulkenberg’s mistake, even suggesting that the German, who has competed in 150 races without a podium — the longest such streak in the sport’s history — was ill-equipped to drive at such a level. “Right now, my thought is, ‘How can these drivers get it so wrong?’ “ he said. “You don’t brake for turn one? I think they should have a higher level to drive in this series.”

The stewards were similarly unimpressed by such a rush of blood, imposing a 10-place grid penalty on Hulkenberg for next weekend’s Italian Grand Prix in Monza, as well as giving him three points on his F1 licence. During the inquest, they disclosed, the Renault driver “stated he completely misjudged the situation and freely admitted it was his mistake”.

Hulkenberg’s sterner critics could be forgiven for thinking that he escaped lightly. “These kinds of mistakes, with high consequences, I think should be reviewed a little bit harder,” Alonso said.

Four cars were taken out of this race as a result of the mayhem Hulkenberg unleashed, with Daniel Ricciardo left unable to continue with a broken rear wing and Kimi Raikkonen limping out with a puncture. This was the same number of retirements caused by Romain Grosjean here in 2012. For that, the Frenchman received a one-race ban.

Hulkenberg was full of contrition. “When I hit the brakes, it locked up the front wheels and I slid,” he said. “These cars are aerodynamically sensitive, especially with cars bunching up ahead of you, as you lose a lot of grip and load. It caught me by surprise here.”

He will quietly serve his punishment in Italy in a week’s time. It is a source of profound relief to all in the F1 paddock that this is the only lingering consequence of Sunday’s disturbing scene.