It’s a huge leap for the boy from Plaistow, East London, and the irony is not lost on Winstone, 46, whose stock-in- trade is the kind of characters who make other men wet themselves with fright.

“My first job was playing a convict in Scum, I was a kid banged up in a borstal,” he says proudly. “From that to playing a king, well, I’ve gone the whole gamut. Henry’s probably the biggest villain of them all. He is a warrior and a lover, he just can’t leave it alone. That’s what gets him into trouble and destroys his soul.”

That he is the lead in such a stellar production, which boasts Joss Ackland, Charles Dance, Sean Bean, David Suchet, Emilia Fox and Helena Bonham Carter, speaks volumes about Granada’s confidence in Winstone. Yet he is humble about being top choice for a role that would have appealed to any of Britain’s A-list.

“It’s exciting,” he says, squeezing into the bench seat opposite. “It’s very brave of Granada to cast me as the king. I mean, it’s not the norm is it? He’s been played before by very talented people and always done very well. I’m just trying to look for different angles, to play him as a man and let everyone else worry about him being the king.

“It’s a tough job: it’s physical, mental, everything, and there’s pressure. I’m not finding it easy, but sometimes you have to put your head on the line, sorry for the pun!” Fittingly, this latest incarnation will be quite different from the atmospheric and rather restrained period films that have gone before. There’s blood, guts and gore aplenty. The director, Pete Travis, sums it up: “This is The Godfather in tights. In Ray we have a man who has a wonderful animal power, very like that which Henry would have had. It’s violent and sexy and that is what the world was like then. People have not seen history done like this before.

“Being the king is about being wonderfully charismatic. I think Ray is probably the only British actor who can do that ruthless power but also be incredibly vulnerable. He can switch from being a little boy to an ogre in the blink of an eye. If you weren’t casting Ray, the only other actors you’d be looking at are Robert De Niro, Al Pacino and Russell Crowe.” High praise indeed for Ray, who adds: “You get the feel of a Godfather thing, in that they are conspiring all the time and there is loads of paranoia. It has a Mafia feel, everyone is jostling for position, everyone could be your enemy.”

Winstone’s transformation took about an hour each day in make-up and costume, with body suits, prosthetics and even padding in his mouth to make him look and sound convincing as the portly monarch.

“The costumes have been good, they are comfortable but pretty heavy,” he says. “By the end of the week I’m dead on my legs. I get to wear all the heavy chains and other jewellery. Some days I’ve felt like MC Hammer. But I usually wear a pin-striped suit, so it’s been a bit of a giggle.”

Winstone lost two stone for the role, working out at a gym and cutting back on his diet so that he was in good shape for the jousting, horse-riding and fight scenes. His only regret is that he wasn’t allowed to do more of his own stunts, for insurance purposes as much as anything.

“I start it and someone else finishes it!” he grins. “But really, it isn’t easy. The stunt boys make us look good. There should be an academy award for stuntmen, though they’d probably just say: ‘put our money up.’ I learnt to ride last year when I was filming Cold Mountain. I’m pretty capable on a horse now. I love it, I wish I’d learnt 20 years ago.”

In those days he might have had the time for that, but not the money. Having cut his teeth in the 1970s cult Brit flicks Scum and Quadrophenia, Winstone’s early promise foundered and he found himself out of work for long spells during the 1980s. He battled on, making the weak BBC One sitcom Get Back with a then unknown Kate Winslet (“a great kid”) before getting the offer seven years ago that would put him back on track: Gary Oldman’s uncompromisingly brutal film Nil By Mouth. Based on Oldman’s bleak South London childhood, it starred Ray as a violent wife-beater alongside his friend Kathy Burke and, suddenly, he was back in favour.

“I was plodding along, enjoying work when I had it but a lot of the time I was unemployed. All I wanted to do was good stuff, but I wasn’t getting offered it until I worked with Gary Oldman,” he recalls. “I don’t want to make it sound worse than it was because when you have a good family around you, you don’t have it hard. I’m a really lucky boy. It was tough in the 1980s but I had my wife’s family and my family and no one was going to see anyone go without. People said I went bankrupt twice, but actually I’ve never been bankrupt because I paid it all off eventually.”

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