True grit: Deadwood star Ian McShane on villainous turns and his days as a Hollywood hellraiser

Ian McShane has racked up an impressive roster of rogues, bounders, cads and villains, not least homicidal pimp Al Swearengen in 'Deadwood'. He talks (extremely) frankly about his hellraising days, on-set sex, and the merits – or otherwise – of some of his Hollywood colleagues

He sure knows how to make an entrance, does Ian McShane. You can hear that distinctive Lancashire voice rolling and tumbling in its unstoppable way from halfway down the Groucho Club stairs. He enters the room like a benign warlord, sharp eyes glancing this way and that, his hands held just so, as if to quell an imminent riot occasioned by his presence. His face is pouchy, and his skin hardly comparable to a baby's bottom, but, features-wise, he's a lot less craggy and dissolute (and scary) than his most celebrated incarnation, Al Swearengen.

He turns out to be good company, launching into Hollywood stories with relish, unconcerned about criticising former co-stars ("Kristin Stewart was just awful in Snow White & the Huntsman. She had this big speech to do, and she couldn't act at all") and confidingly matey about his old drinking buddies ("Oliver Reed? Loved him. He once told me, 'I'm growing my own marijuana – would you like some?' The two of us sucked at it for an hour. I thought, what the fuck is this – grass or grass cuttings?").

When I tell him I'd admired his leather get-up in Pirates of the Caribbean: On Stranger Tides, he sighs. "It was the wardrobe mistress Penny Rose's idea. She woke one night and said to herself, 'Of course – he's a Biker Pirate!' When I was trekking through the Hawaiian heat, clad in 35 pounds of black leather, I was thinking, 'Thank you, Penny...'."

McShane has played a lot of regal roles lately. After half a lifetime playing charming villains – scoundrels, rogues, smiley gangsters, iffy antique dealers and the most dangerous saloon landlord in the Old West – he's settled into a late career radiating lordly, indeed kingly menace. He was King Brahmwell in Jack the Giant Slayer, a bishop in Pillars of the Earth, the leader of a dwarf gang in Snow White, a king in Kings and Blackbeard in Pirates. Now 71, he is very busy.

He spent this summer in Budapest, making Hercules for MGM with Dwayne 'The Rock' Johnson as the titular superman. Did he enjoy it?

"It was fine. Budapest is a very pretty town and I learnt a lot of useful things over the 19 weeks." Like what? "Like chariot training – and fighting with an extraordinary weapon with multiple blades, like a very early Swiss Army knife." He plays Amphiaraus in the film ("Part prophet, part seer, part warrior," deadpans McShane, "and all man") and is surrounded by famous British actors: John Hurt, Rufus Sewell, Joseph Fiennes, Peter Mullan.

"Johnny and Pete play the bad guys," says McShane. "Rufus Sewell plays Autolycus, which the Americans pronounce 'Oughta-like-us'."

It's an American film with an American director, Brett Ratner. Why are all the Brits in it? "We add gravitas," he says simply. "We give it weight. The Americans know there's nothing worse than someone saying, 'Have ya met my brudder Agamemnon?' They prefer to have real actors, who give the impression they know what they're doing."

McShane stars as Al Swearengen in 'Deadwood'

In complete contrast, McShane also co-stars in Cuban Fury, coming out on Valentine's Day, a terribly British comedy about a hopeless schlub called Bruce (Nick Frost) who fancies his boss (Rashida Jones) but can't think how to win her heart until he sees her salsa dancing in a pub. Wait a minute – he, Bruce himself, used to be a teenage salsa star until some Terrible Thing happened. If he could only get back to salsa match-fitness, he might succeed in parting her from her foundation garments. He hires a long-haired, swarthy salsa teacher called Ron...

"I did Cuban Fury because it's got a really good cast," says McShane. "Nick Frost is a comedian who can really act. He's got low-key gravitas. And they'd got Chris O'Dowd and Rory Kinnear, and Rashida Jones – you know, Quincy's daughter, she's a gifted comedian and a writer – to play the feminine lead."

Wasn't a small-scale British comedy infra dig for someone like him, who mostly plays kings and pirates and gangsters in US blockbusters? McShane is unbothered. "What could be nicer? It has a really funny, charming script by Jon Brown, who looks about 12 – well everybody nowadays looks about 12. It was the first film directed by James Griffiths, who directed Episodes, that TV thing about Matt LeBlanc ... He's a very smart guy."

The film features a trademark McShane shot: the actor's face in scary close-up, regarding the hapless Frost with that dead-eyed stare before which so many losers have quailed over the years. A long way from the crinkly-eyed charm of TV's Lovejoy, it defined the character of Al Swearengen in Deadwood, the HBO series about the South Dakota gold-mining camp that became a town in the 1870s and resisted becoming assimilated by the United States.

McShane says his role as the foul-mouthed, homicidal proprietor of the Gem saloon and cathouse, was the best and most complex role he ever had. And it was a role he inhabited with gusto. Had there been issues about his British accent? Had he tried to do a fake-American accent, like Hugh Laurie in House?

McShane looks disdainful. "I always thought that accent was all that House was about. No offence to Hugh, but it sounded like someone hanging on to an American accent. With Deadwood, I did the audition, we did a read-through on the set, I was the only Limey bastard, in front of all these guys. David Milch [the creator] said, 'I'm going to invent some background for why you sound like that'. And I said, 'I'll invent my own accent'. Because [he essays a ludicrous southern-belle fluting] Ahn caint towk lahke in thay-att kinda Murrican ac-saynt." Which is why, although Swearengen is clearly a Limey, he pronounces "cocksucker" as "kacksucker". In case you were wondering.

McShane clearly idolises David Milch, who wrote and co-produced the series. "David has a refreshingly direct attitude to acting. I had one scene with the whore, Trixie. Al calls her up to his room, to admonish her for something she's done. Now remember, I'm working here with a woman actor I've met maybe a week before. Anyway, David is there with the director, watching the scene. He looks at me and says, 'Ian, you have to grab her cunt'. I thought, that's not the first directorial thought that springs to mind, is it? But it was absolutely true to the character, and put the actors at ease with each other. He's so direct – not like some directors who go round the houses for 20 minutes."

McShane is 71 but shows no signs of slowing down (Kalpesh Lathigra)

Milch's working methods were unorthodox – he'd give the actors just a few pages to learn, watch to see the outcome, then go away and re-write the scene – but McShane took them as signs of genius. "He wrote organically. He wrote from what he learnt from a scene and went forward. His vision of the show was constantly moving forward. David never lost sight of the fact that it was about the beginnings of a country, about lawlessness, passion, power and human beings. He cared so much about the characters' unfolding."

Something else that was unusually organic was the set. The cast and crew didn't disappear to hotels each evening. They stayed put, living together on a ranch 30 miles north of Los Angeles, and rose every morning as if they were inhabitants of Deadwood.

"Everyone was there together," says McShane, eyes shining. "Writers, editors, riggers, animals – we never moved out. You didn't have to be somewhere else every day. You were the village. When we came on set every day, the extras would be there in costume and character, shouting 'Mornin' Al!'."

Deadwood aired over three series, 12 episodes each, between April 2004 and August 2006. It was a critical smash-hit, and won eight Emmy awards, including Best Actor for McShane. And suddenly it was all over. HBO announced it wouldn't pick up the expiring options of the actors for a fourth season. David Milch said he hoped to make two two-hour TV specials instead of a fourth season, but the project dwindled. It was left to an exasperated McShane to announce, in 2009 on The Daily Show With Jon Stewart, "Deadwood is dead!".

McShane is able to claim, while still being given starring roles, that he's been in movies for half a century. He was the star in his first film. It happened like this. Born in Blackburn, Lancashire in 1942, the son of a Scottish footballer (who played for Manchester United) Ian breezed into the Royal Academy of Dramatic Arts after grammar school. There he met John Hurt, who became a lifelong pal.

"Johnny and I were best friends at Rada. He was a year ahead of me, and had been cast in The Wild and the Willing. We had the same agent, and Johnny suggested me for the lead in the movie. I met them, they said, 'Can you come for a test?' and I took the day off school. I got a Greenline bus to Uxbridge, to Pinewood Studios, and said, 'I'm here to do a screen test'. Then I took the bus back to school. And they offered me the part the next day. I told the head, 'Sir, I lied, I didn't go to the dentist, I did a screen test'. He said, 'I might not be able to give you your certificate because of that'." He laughs, and briefly looks rather like the cocky young student he played in the film – a natural leader, even at 20, and a convincing rebel, who tells the old farts at the bar, "OK, we didn't die in the war – we're really sorry about that!".

Why didn't the film catapult him into rebel stardom? "Because it was J Arthur Rank's attempt to capture the new wave of teenage rebellion," he says. "And they didn't follow through. If only we'd had Karel Reisz or someone in charge."

McShane's first role, in 'The Wild and the Willing' (Rex Features)

He was launched, though. TV followed with parts in Armchair Theatre. In 1967, he appeared in London's West End in The Promise by Alexsei Arbuzov, alongside Ian McKellen and Judi Dench. He was in the original cast of Joe Orton's Loot. "It died in Wimbledon," says McShane sadly. "Kenneth Williams was in it, very nervous about being in a straight play by Orton. The first night he came on in a kind of fascist raincoat, looking like a cleaner. The second night he was in a deerstalker like Sherlock Holmes. It was fascinating to watch. He hadn't a clue how to play the part."

Speaking of gay matters, I said, is that story about you and Richard Burton true? He laughs. "You mean the scene in Villain [the 1971 movie based on Ronnie Kray and his driver]? Oh yes. I got on very well with Richard. During shooting, we were discussing the upcoming gay love scene. My hair was very different in those days – it came down to here. He turned to me and said, 'I'm very glad you're playing this scene, Ian'. I said, 'Thank you Richard'. He said, 'You know why, don't you? Because you remind me of Elizabeth...'."

After his early success, McShane happily admits, he went spectacularly off the rails in the 1970s. "I went to live in America in 1975, because I was pretty bored here. I was sick of the black-outs."

My God, I said, sympathetically. You mean you were drinking so much...

"No!" says McShane, "I mean the power cuts in 1974! There was fuck-all happening in the UK, so I went to America, and got divorced a year later. I've lived there, on and off, from 1975."

In London and California he became a party hellraiser, hoovering up drink and anything else available ("I was an equal-opportunities abuser"). He kept acting, though: he specialised in villainy and swashbuckling on film and historical impersonation on TV: in five years he played Christopher Marlowe, Benjamin Disraeli, Judas Iscariot and Prince Rainier of Monaco. His second marriage failed around the time he met Sylvia Kristel, of Emmanuelle fame, on the set of The Fifth Musketeer. "I met her in 1977, we had a crazy year-and-a-half. It was very nice, but mostly fuelled by mountains of... whatever. Then we went our separate ways."

He and his third wife, the actress Gwen Humble, have been together since 1980, and live in equanimity in Venice Beach. He has no immediate intention of saying no to movie parts as they roll in. But does he yearn these days for more nuanced roles than kings, dwarves and pirates? "I enjoy every role I do," says McShane, with sleek satisfaction. "Next year, I'll probably be doing Steven Berkoff's modern gangster version of Agamemnon, which will be good. You set paths for yourself, but as you get older, things change. If Deadwood had gone on another two years, I wouldn't have got as many movies made. You don't know where life takes you."

It takes you, I say coldly, into making a ludicrous animation called Kung Fu Panda, where he was the voice of a snow leopard called Tai Lung. How is that an interesting place to end up?

"You know how that came about?" asks the indefatigable McShane. "The people at DreamWorks had taken a five-minute speech of Al Swearengen's and re-done it as an animation from a tiger's mouth. I said, 'How can I say no?'"

'Deadwood' is repeated on CBS Action from Friday at 10pm