The fearsome Wareing/Ramsay partnership lasted for fifteen successful years, and made stars of them both. While Ramsay attracted interest for the raw fury of his appearances on Boiling Point, on the same programme Wareing can be seen working quietly and composedly in the background – which offers clues to the dynamic of their relationship as it was. He has since admitted that working weeks regularly consisted of six eighteen-hour days – “I never slept on the kitchen floor, but I came close”.

His first solo project, albeit backed by Ramsay, came at Pétrus, where he won two stars of his own and was lauded for his ability to produce regal dishes that married his humble upbringing with his classical training. But he grew increasingly restless working under the aegis of his friend (and best-man) Ramsay, and after a legal dispute with Gordon Ramsay Holdings over the acquisition of Pétrus, started to build his own empire – renaming Pétrus as Marcus Wareing at The Berkeley before opening ‘English brasserie’ The Gilbert Scott in 2011 and the more laid-back Tredwell’s in 2014.

After what has come before it should surprise nobody to see Wareing take on such a big a challenge as MasterChef this far into his career: where others see stress and hassle, he sees the potential to be better – and finds solace in the rewards of his toil and sacrifice.

The redesign of his restaurant Marcus is a case in point. Here was a restaurant many considered a market leader – practically royalty as far as the London restaurant scene goes. But Marcus, ever the contrarian, felt that a freshening up was in order – and not just cosmetically.

“I look at the busiest places in London and they are all very relaxed,” he says. “One of the things that has changed for me – and maybe it is my age – is I’ve started to find fine dining very tiring; where you sit for 2 or 3 hours or maybe more in a restaurant and you have to really focus on what’s being served to you. I wanted to change that at The Berkeley.”

Despite the obvious limitations to how informal Marcus can go (“I am in a five star hotel in Belgravia. I can’t afford my managers to look sloppy and untidy in their jeans and their chinos!”), the change in tone is tangible.

“I think the customer should dictate what they want to do. You’ve got the businessman who’s closing the deal: he doesn’t want the 8-course tasting menu but he wants to impress. Now, at restaurant Marcus, if he turns round to my Maitre D and says ‘I want to be done in 2 hours on the dot, I want three courses served only’ – and that’s what I what to send – we do it, hands down.”

The swagger remains, and it is clear that he feels he is onto something with both the redesigned Marcus and new restaurant Tredwell’s (“lots of music, great staff, great food in a fucking cool environment”). He is similarly forthright in his rebuttal of the notion that the guide could mark him down for relaxing the dining experience at Marcus, saying: “That’s all in a chef’s head, absolute bullshit. Michelin judge you for what you put on a plate. It’s all about good food.”

Nevertheless, the perfectionist still hasn’t found perfection (do they ever?), and he is quick to temper any enthusiasm by outlining the work still to be done.

“I’m not there yet. I’ve still got work to get the message across. I had a customer – an inspector for a guide – come in to us and he said: ‘Marcus, I can’t see where you’ve made it more relaxed.' And it was only once I had talked to him and expressed what I am doing as a person, a leader and as a restaurateur. He only then understood where I was going. I don’t believe that we can change overnight, it takes time.”

So does he fear that MasterChef will get in the way of his day job?

“My job, and what I do, is everything to me, and becoming a MasterChef The Professionals judge is complementing that and I hope enhancing my knowledge of the wider industry. I get up in the morning to cook; it’s what I do. I absolutely love food. MasterChef is something that I’ve added into my day.”

The truth is, however hands-on the chef continues to be it is impossible for one man alone to run such a well-oiled operation across three restaurants.

The trick, one imagines, is to surround yourself with the right people – those that buy into your vision and understand your ethos. Luckily, Marcus has some brilliant people around him, such as the Head Chef at The Berkeley, Mark Froydenlund, and Group Operations Director, Chantelle Nicholson.

Perhaps it is the trust in those around him that has allowed Marcus to “become a much more relaxed person” – which he hopes will come across on the programme. It is surely no coincidence that this year has also seen the chef join Twitter - a bold move to take before MasterChef goes out to much social media frenzy – while he has even found time to help Bradley Cooper harness his “inner chef” for a film role.

But soirees with A-listers or messing around with 140 characters are not what sate his ambition, and it is to the redesign of Marcus that he comes back to when contemplating his newfound happiness.

“I am happier now because I’ve finally built my restaurant - the way I want it to look. And I feel very much at home. When I closed the restaurant down in January of this year - that was a massive turning point for me. I could then start to become the person I always wanted to be. Which is me. Whereas before I was a clone of the Gordon Ramsay group and my restaurant still looked like Pétrus. And it used to piss me off. Well, I kept my head down for five years, I built the funds to be able to build the group and closed it down and refinanced the thing. That’s what we’ve done. Now I can start building for the future.”

The passion and steely-eyed determination are still there, of that there is no doubt, but there is no real hint of bitterness or anger in his voice as he reflects on the split from GRH, and he is warm and generous in interview. This is not Marcus Wareing the hot-headed chef, or indeed Marcus Wareing at the Berkeley, stifled by the formality and the sense that he is a “clone of the Gordon Ramsay group”. This is just Marcus. To try a bit of cod-psychology, it may just be that for the first time in his career he feels comfortable with it being that way.

With things this good, the obvious question for a man as driven as Wareing has to be what comes next? Does he see another restaurant on the horizon?

“Never say never… but right now three is more than enough!”