David Thewlis is covered in muck. His head is bald and his beard is long. But that’s the way the award-winning British actor likes it.

“I quite enjoy having a shaved head, because it means I can get up in the morning and I know what I look like,” he says, chuckling. “You don’t have to bother with your hair. I recommend it.”

It is May last year, and Thewlis is sitting in the afternoon sun on the set of The Artful Dodger in Lilyfield, in Sydney’s inner west. Softly spoken but with a definite twinkle, he is in the middle of filming the overdue second season of Disney’s historical romp, in which he plays one of the more controversial characters in literature: the master criminal and child trafficker Fagin from Charles Dickens’ Oliver Twist.

However, instead of drawing directly from the source material – in which Fagin is described as a “reptile” with “fangs” similar to a dog or a rat and, most controversially, as a “loathsome Jew” (Dickens eventually made revisions in later editions of the book and wrote an apology to a reader) – Thewlis turned to another criminal mastermind.

“I used to know, actually, back in Britain, this man called Bruce Reynolds, who was the mastermind of the Great Train Robbery in the ’60s,” says Thewlis. “Now, through strange circumstances, I got to know him quite well and became very good friends with his son [Nick], because he was a consultant on a film [Gangster No.1] I did in the ’90s. So Bruce became a friend of mine and all his extended gangster friends.

“So, my research, really, is with the man who pulled off the biggest heist of the 20th century in Britain, and was the mastermind of that. He was absolutely a really wonderfully beautiful man, actually, and he would be very happy to talk about that crime.

“You could always ask him about it because it wasn’t like you can’t ask Bruce about the train robbery – it was always, ‘Go on, ask him about it’ because he loves talking about it, and he’d always start off going, ‘We was thieves, Dave, we was little thieves.’”

As it so happened, those “little thieves” operated in Clerkenwell, the once desperately poor London suburb where Thewlis now lives.

“I live, maybe, 200 yards from a road called Saffron Row, which is where Fagin, the original Fagin [the real-life criminal Ikey Solomon] that Dickens based [the character] on in the book, lived,” says Thewlis. “It’s where he had his gang of children, and where the Artful Dodger first meets Oliver is Clerkenwell Green, which is right opposite my home.

“So I live completely in that world, and where I used to know Bruce, the train robber, was also in this area … so it’s always been quite present.”

(If ever you wanted a sign that your life is quite boring, try talking to one of the stars of Harry Potter – Thewlis played Remus Lupin – while he regales you with stories about his great friend who is a criminal legend. Anyway, back to the story…)

In The Artful Dodger, Fagin lands in Sydney in the 1850s (he dies at the end of the book, but has been resurrected for televisual purposes), where he meets one of his former charges, the pickpocketing prodigy the Artful Dodger, aka Jack Dawkins.

Played by Thomas Brodie-Sangster, who is best known for The Queen’s Gambit and Love Actually, Dawkins is now a surgeon who learnt his trade in the navy, and the pair are drawn into criminal activity again like moths to a flame.

“It’s not like Fagin’s trying to be rehabilitated,” says Thewlis. “Fagin is proud of being a criminal, he sees it as a noble art, he celebrates it. He’s not ashamed of himself, and he thinks it’s a fine job.”

If you haven’t seen it, the show is a complete hoot. Thewlis and Brodie-Sangster are the ultimate odd couple, while Maia Mitchell, who plays aspiring surgeon Lady Belle, adds crackle to their pop.

“Basically, the relationships between Fagin and Belle and Dodger it’s on, or it’s off, or it’s falling apart, or it’s blossoming, so it’s kind of this constant up and down roller coaster,” says Brodie-Sangster, who arrives to chat also covered in muck, but with added glitter so he sparkles on camera (“It’s a Twilight romantic sparkle filth,” he decides).

Season two has expanded the Australian cast, adding Luke Bracey as Port Victory’s new commander Inspector Henry Boxer, and Jeremy Sims as the Duke of Shrewsbury, the brother of Port Victory’s governor. The set has also been extended, with most of the filming now taking place in Lilyfield, where the roar of overhead planes is understandably edited out, and a Hollywood-style back lot was created for the multimillion-dollar show.

Season two picks up six months after Jack (Brodie-Sangster) was sentenced to death for the murder of Captain Gaines. Desperate to clear his name, Lady Belle turns to Fagin for help. Needless to say, it does not go well.

“I’m very fatherly protective of him, to not be hung,” says Thewlis. “Therefore, I don’t want anything to do with Belle. I loathe Belle, which is very funny, I can’t stand her, and just don’t want anything to do with her because she represents an existential threat to me and my ostensible son.”

For Brodie-Sangster, the love between Fagin and Dawkins is what threads the show together.

“[Fagin’s] always been a bit of a fatherly figure,” says Brodie-Sangster. “He’s the closest thing that Dodger has to a father – a messed up father – but there is a form of love there. It’s a bit of a weird, strange, twisted form of love, but it’s certainly love.

“Love is the overriding feature that runs through this whole show. I mean, there’s a role reversal, [Fagin’s] been my servant convict in season one and one of the reasons, one of the terms in which I’m released [in season two], is that I have to be looked after by a trusted member of society. And someone decides that that trusted member of society should be Fagin.”

In season one, Brodie-Sangster was often elbow-deep in blood and gore (an amputation springs to mind), and while he enjoyed it, he was also happy to step away from surgery a little bit in season two.

“In reality, I’m very squeamish,” he says. “It’s part of the trickery of the film industry, and that’s fun. I just see it as fun. And it’s impressive, too, when you’ve got blood pumping out of a shark wound. It’s very cool.

“But I think we brought down the gore [for season two]. I was always pushing for that [gore in] season one, but I think having watched it, that we could get away with having little bit less [blood].

“I had friends as well that had young children that started to watch it and [thought] maybe this isn’t quite appropriate. I think, maybe, we lost out on a segment of our audience. Also, I’m a believer in the power of suggestion. You can put a scene out, and you don’t always have to show extreme close-ups of exactly what we’re doing. You can leave that to the audience.”

The Artful Dodger (season two) streams on Disney+ from February 10.

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