By way of introduction to his new cookbook, Pierre Koffmann sets out the philosophy that has made him one of the three or four most influential chefs to work in Britain in the last half century. As with all of Koffmann’s creations he has distilled his methods to their essence. The philosophy goes like this: “I am a typical French chef. I work like any chef; I am hard to work for. I want the task done the way it should be. It is all about using few but the right ingredients. You have to be in love with cooking. You must enjoy eating. Oh, and you need a bit of luck!” That’s all.

The secret, he insists, is that there is no secret. Koffmann is now 68. In the kitchen most days for the past 50 years he has applied himself to these principles every lunch and every dinner. He made his name at the Roux brothers’ Riverside Inn at Bray, then at his own restaurant, La Tante Claire in Chelsea where, in 1983, he became the second chef in Britain to be awarded three Michelin stars. At La Tante Claire he was both mentor and occasional tormentor of a generation of chefs who watched him at work and learned: Marco Pierre White, Bruno Loubet, Tom Kitchin, Jason Atherton, Helena Puolakka and Gordon Ramsay all passed through his kitchen. These days they fall over themselves to credit him with all sorts of muscular praise. Kitchin says working with Koffmann was “like I was on a bridge. I could have gone back to where I was nice and comfortable. But instead I crossed the bridge, and nothing scared me after that. It gave me mental strength.” Puolakka, who was his sous chef at Tante Claire for five years “still gets goosebumps” thinking about his impromptu mid-service tasting menus. White suggests that “Pierre influenced me on the plate more than any chef I have ever worked with” and cites Koffmann’s signature pig’s trotters with morels and veal sweetbreads as his favourite ever dish. Back then they knew him, for his style, for the way he attacked each service, as “the bear”.

Sitting at a table in his culinary home of the last decade – Koffmann’s at the Berkeley Hotel – the moniker is hard to credit. He is courteous, charming, quick to laugh. But he insists it was well-earned. Before he was a chef, Koffmann was a rugby player – a lock forward or a number eight – in his native Gascony in the south of France. He played for his home town Tarbes, and for Toulon, before decamping to London – initially to watch a rugby match at Twickenham – and the ruck and maul of the kitchen.

“I always thought of being in the kitchen like being a captain of a rugby team,” he says. “I liked to think I was Jean-Pierre Rives [the buccaneering France skipper of the 70s] at the stove. It’s the same in that you want your chefs to follow you into war each day. I looked after them well, but there had to be that intensity. Always a very small team. Even at Tante Claire we had never more than seven or eight in the kitchen including myself.”

It was, too, about always being at the top of your game. Koffmann stressed the importance of rest. “We were closed Saturday and Sunday. We started quite late and I insisted they went off and relaxed or slept for a couple of hours each afternoon. We had two weeks off at Christmas, two at Easter and in August. But when we were there, I expected a great deal.”

Times have changed a little for Koffmann now, but he still feels, with a grin that “in the kitchen you have to be prepared to be a shit sometimes. I always wanted pressure. I think you do your best work when every service is a kind of a fight.”

He fears, with a laugh, he is becoming a grumpy old man. Or at least after a day on his feet his joints make him feel like that. “Otherwise it is like yesterday.” His routine hasn’t changed much, though he can only really manage to eat one good meal a day now. He is proud that his disciples have mostly gone on to fame and fortune, but the attractions of having restaurants bearing your name in Shanghai and Qatar are lost on him. “My quality is to stay in one restaurant and cook every day,” he says. “I think it is your job to know the quality of everything.”

For the first eight years of La Tante Claire that was literally the case. Even in 1985 Koffmann had to get all his food from France because the markets in London didn’t offer what he needed. “I had a guy who drove up on a Wednesday, delivering 20 poulet de bresse, pigeons, foie gras, mushrooms, everything. I used to go through everything by myself. One day Marco said, ‘I’ll do it for you’ – and he did it as good as me. The first one.”

Despite his insistence that it was mostly perspiration not inspiration, I argue that there must have been magic moments. Did he often surprise himself?

Sometimes, he says, and he recalls not a dinner at Tante Claire but a Sunday on the beach in Wales with his family. “The kids went crab fishing, we had a bucket, you know, full of these little crabs, and the English idea is to throw them back. I cooked them instead, made a soup. I don’t know why but on that day the soup was just perfect, the freshness of the crab just out of the sea. I could never make it again. So I remember that.”

Koffmann doesn’t feel the need to reach for Michelin stars these days, but he is as determined as ever to keep exploring and refining and recreating the tastes he learned in his childhood. He has a theory that most great chefs learn from their grandmothers – they have more time to teach. His mother ran a cafe in Tarbes but it was on summer holidays on his grandparents’ farm that his passion began. It was only a small place, but apart from some tripe or maybe some foie gras his grandmother would get in the village, everything they ate came from the farm: a lot of rabbit, chicken, duck.

His grandmother never came to London but when he opened La Tante Claire she offered to send him two dozen chickens – “I had to explain you couldn’t just send live chickens from Gascony to London.” After his grandparents died the farm was sold. He can hardly bear even to drive past it when he visits now.

I wonder if he imagines retiring to France, but he suggests not. In fact, he has no plans to call it a day. It’s strange because from the age of 25 he says he thought about retirement. “When I was young I took a good insurance,” he says. “When you are 25 you cannot imagine what it might feel like to be 45, so I thought that was a good age to retire. One day I was 45, and I thought I will go another five years.” Koffmann’s first wife died when he was 50 and he moved La Tante Claire from Chelsea to the Berkeley. “Then at 55 I thought, OK, I need to stop now, take advantage of my insurance.”

For the first year he went travelling in search of tastes – to Japan, China. Then, back in London he would spend the morning wondering where to have a morning cappuccino, then where to have lunch, “and I then trying to work out what to do with the rest of the day. A little siesta. Then maybe see my then girlfriend – now my wife – and I would be in bed by 9pm or 9.30pm. I lay there one time and said: ‘Pierre, if you keep on this way, you will be dead of boredom in a year.’”

He first was asked back to do a pop-up restaurant at Selfridge’s for a week. In the end he did eight weeks: 120 seats sold out; 3,200 pigs’ trotters. “While you work, you are like a machine, a car,” he says. “Everything moves like it has always done. Then the moment service was finished my legs were like two broomsticks.”

He couldn’t resist the challenge of another restaurant, though. And the appetite persists. “You go to market and you see the first asparagus, or the first peaches and it gives you ideas. If you are not excited by the product then you must stop. That hasn’t happened yet.”

The next change is being forced upon him. Koffmann’s at the Berkeley is closing at the end of the year because of a two-year renovation. Koffmann is weighing his options. “I am not ready to retire again,” he says. “So I need to find a little place to cook. Everything changes, you have to adapt.” He might take some time off to take stock, he says. But ideally not longer than a fortnight.