Watch Chabal's monstrous tackle on Chris Masoe

Watch Chabal's full-blooded charge at Ali Williams

Rarely has the term “impact player” seemed so appropriate. At some point during the second half of England’s World Cup semi-final in Paris on Saturday evening, Sébastien Chabal will be unleashed from France’s replacements’ bench, a wrecking ball designed to make huge indentations in England’s defensive wall.

Off the field, he has had just as big an impact over the past few weeks. His imposing features — straggly beard and long, unkempt hair — have glared down from billboards all over France, earning him the nickname “The Caveman” and making him an iconic figure of his country’s World Cup. He has attracted thousands of French women to rugby — they are known as les Chabalistes — and has been voted the sexiest player of the tournament, described by one of his fans as “the antithesis of metrosexuality”.

Happily for Chabal, his admirers also include Bernard Laporte, the France coach, but this has not always been the case. It is more than seven years since Chabal, 29, made his debut for France, but for several years he was mistrusted by Laporte. That changed during an otherwise miserable tour to New Zealand during the summer, when France lost 62-10 and 42-11 to the All Blacks, but Chabal enhanced his reputation with some memorably powerful performances.

Like so many supporters of Sale Sharks, for whom he will play for a fourth season after the World Cup, Laporte could no longer resist Chabal’s rugged charms. Normally a No 8 for Sale, the France coach has found him a fitting role as a replacement lock who emerges to strike fear into the hearts of tiring opponents. “He has that X-factor when he strides on to the pitch,” Kingsley Jones, the Sale head coach, said. “The opposition take one look at him and know they’re in for a tough afternoon.”

For those who are unfamiliar with the brutal ferocity of Chabal’s play, a quick visit to YouTube provides ample evidence. One monstrous tackle on Chris Masoe, the All Blacks No 8, has been watched more than a million times and termed as le plaquage du siècle — the tackle of the century.

Another snippet from that summer tour shows his full-blooded charge at Ali Williams that left the New Zealand lock with a broken jaw. These videos do not appear to have a restricted age limit, but if your children are watching, you may wish to shield their eyes.

What these clips show is Chabal’s extraordinary strength. “He’s without doubt the most naturally powerful athlete in world rugby,” Nick Johnston, the Sale head of physical preparation, said. “You can look at the likes of Andrew Sheridan [the England prop] and Jerry Collins [the New Zealand flanker], they are players who have trained themselves to be powerful. But in terms of natural attributes, Sébastien has really been blessed.”

At 6ft 3in and 18st, he is not unusually large for an international forward, but, the beard and the hair aside, virtually everything else is muscle. “He has an incredibly low body fat reading,” Johnston said. “His percentage is around 7.5, whereas most professional players have about 14 per cent. When he first came to us three years ago, he weighed 107kg and he now weighs 115kg, but he’s very lean, so it’s all the right sort of weight.”

There will be nothing subtle about Chabal’s approach when he faces England on Saturday. He will run straight, hard and fast and, when he spots a would-be tackler, he will attempt to run over him, rather than round him. In keeping with his primeval appearance, Chabal can make rugby look a thrillingly elemental sport.

So if he is such a force, why has he not won more than 35 caps? Although he could not be described as lazy, Chabal’s contributions in the past have been too sporadic for many coaches. A bullocking run could often be followed by a short spell of introspective grazing away from the ball.

“Twelve months ago, we said to him ‘if you’re going to go to the World Cup, your workrate needs to improve dramatically’ and he took that on board,” Johnston said. “At the end of last season, he was coming in for three or four extra sessions a week. He’s a very good trainer, but he needs to be set specific targets. He particularly enjoys our endurance circuits, which include tug-of-war and wrestling matches, all designed to replicate his game movements.

“When he wrestles against Sébastien Bruno [the Sale and France hooker], all the lads stop training to watch because it’s a real battle. And he once dead-lifted the same weights as Andrew Sheridan, which doesn’t happen very often. We also have our players pulling our Ford Transit kit van with a bungee rope around their waist. Sébastien is very, very good at that.”

Having followed Philippe Saint-Andre, the director of rugby, from Bourgoin to Sale, Chabal is settled in Cheshire, where he lives in Cheadle Hulme with his wife, Annick, and two young daughters.

It was while he was awaiting the birth of his first child, Lily Rose, almost three years ago that he started to grow his beard and his hair. By the time Lily Rose was born, his wife liked the beard and it had become an integral part of his cult image at Sale. During the World Cup, his club’s Chabal clothing range has been sold out twice over. “I have told him that he looks like a gypsy and that he looks better with short hair,” Lionel Faure, his French team-mate at Sale, said. “But he just shrugs his shoulders, laughs and says, ‘I don’t care.’ ”

Chabal seems to have taken to most things about the English way of life, except for the food, which is a regular source of complaint. He treasures his relationship with his local butcher, who supplies him with choice cuts of veal, and believes that Marks & Spencer is the only English outlet to supply decent French bread. Otherwise, he is a happy, home-loving family man.

“It’s funny that he has this image as an aggressive caveman because off the field he is just the opposite,” Faure said. “We go out for an espresso, we play poker and during the presidential elections, we talked a lot about politics because Sébastien is very well informed. But most of all, he enjoys being with his family. He’s just an ordinary man.”

Animal appeal

Born Valence, December 8, 1977

Height 6ft 3in (1.91m)

Weight 18st (114kg)

Body fat percentage 7.5

Clubs Bourgoin, Sale Sharks

Position No 8 or second row

Caps 35

Nicknames SeaBass, The Anaesthetist, The Caveman

— Lives in Cheadle Hulme, Cheshire, with his wife and two daughters

— Credited with attracting thousands of French women to rugby and has been voted sexiest player of the World Cup

— Chabal T-shirts have done a roaring trade in Sale during the World Cup; a third reprint has been ordered

— If there is a “hair” apparent to Chabal as rugby’s “caveman” in the England camp, it has to be George Chuter (see image 3, above), the hirsute hooker, who has admitted that “Chabal is my idol in terms of facial hair, but I’m not in his league”. Chuter’s style was not born out of a bid for a new image. “I decided to grow it because I can’t be bothered to shave,” he said.