Georgian magic of old England on the BBC

This is an extraordinary fact when you consider Marsan's screen time and range, not to mention his unique and unmistakable visage, ("I'm not handsome. Men don't want to be me and women don't want to sleep with me"). Born in the East End of London to working-class parents, Marsan worked his way up after drama school through small parts where his native vowels put him in various crime and geezer roles. But he actively fought to be seen as more than just another ensemble Cockney, and racked up diverse parts in Gangs of New York, Guy Ritchie's Sherlock Holmes reboot, Paddy Considine's Tyrannosaur, and the underrated, riveting, Southcliffe for ITV, not forgetting his turn as tested driving instructor Scott in Mike Leigh's Happy Go Lucky (En-Ra-Ha!) But Marsan's latest role has the internet abuzz with anticipation: that of Mr Norrell in Jonathan Strange and Mr Norrell. Norrell is repeatedly described in the book as being small, nervous, fussy, and somewhat beady-eyed. He's half of the story, but could be construed as the villain of the piece. What did Marsan make of him? "I like him. I find him a fascinating person. I'm not really into fantasy, but I'm into characters. And Mr Norrell is fascinating because he has all of this information, but he's a miser and a hermit."

But what is Jonathan Strange and Mr Norrell? It's a Hugo and Nebula-award winning book by Susanna Clarke, a work of fantasy that more comfortably sits alongside the works of Austen, Dickens, and Smollett than Tolkien or Rowling or Le Guin. It's huge in scope, impressive in plotting, and masterful in execution. In short, it's a tale of two Georgian gentlemen who endeavour to bring magic back to England. It's a wonderful, fulsome read; the kind of book truly for booklovers, an anti-DaVinci Code. And the BBC have made it into a television series.

So how did Marsan get involved? The old-fashioned way: he knew the director, Toby Haynes. "Myself and Ewan Bremner did a short film with him when he first left drama school." Cut to ten years later, Marsan gets sent the script, does a go-see, and lo and behold, it's Haynes behind the camera. Liking the script, he naturally felt more confident that the production was in such capable, familiar hands. The film world is a small place; people are bound to run into one another if they work enough. But what's most interesting about this story is that Jonathan Strange and Mr Norrell ever got made at all.

The journey of Strange and Norrell from page to screen has been a long one. The rights were snapped up by New Line Cinema soon after publication in 2004, with, inevitably, Peter Jackson in mind to direct. This version of the production languished in no-go obscurity until Cuba Pictures bought the rights, and brought scriptwriter Peter Harness (Doctor Who) together with director Haynes (Sherlock, Being Human). It's now a full-blown, rather expensive-looking, seven- part BBC drama. Bells and whistles were not spared.

Eddie Marsan is the retiring and reluctant saviour of English Magic, Gilbert Norrell. Bertie Carvel is the impetuous, romantic, scatterbrained Jonathan Strange. Susanna Clarke's nuanced, funny, thrilling and very accomplished novel deals not only in the fantastic, but also with the historical. So whilst spells are cast, and silver dishes of water are consulted, Waterloo and the Peninsular War figure largely in the story. It couldn't possibly be done well on the cheap, or on the short. Marsan compares Jonathan Strange and Mr Norrell to the Lord of The Rings in scope. "This is indicative of the confidence in television now. This is such a huge, ambitious production." He further mentions that the BBC's Little Dorrit, from 2008, was only made in half hour episodes because that's what producers thought could hold people's attention. "Jonathan Strange and Mr Norrell shows how far tv has come."

And it does look lavish. Money, time, and a great deal of care was spent in making this house brick of a book come to life. At the centre of it are the two men, and Eddie Marsan had a very clear idea that he had to start his creation of Norrell with the thing that is Strange and Norrell's raison d'etre: magic. "Magic speaks to that part of the subconscious that is creative and spontaneous, and is what happens in spite of ourselves. It's scary because we're not in control of it. In the way they each deal with magic, Jonathan Strange and Mr Norrell are both sides of the human brain." Which is which is pretty clear. Norrell is a Yorkshiremen (as are most of the characters,) so getting the accent right was a must. And as Norrell is also a gentleman. Marsan said he turned to the voice of Alan Bennett for inspiration. Though this rather conjures the character of Norrell as a corduroy sorcerer, the reality is different: Marsan's portrayal gives Norrell a tightly-wound, nervous aspect, but one with resolve. A resolve that is key to the plot and leads to something rather messy and sinister.

But in spit of Norrell's dis -amiability, Marsan likes him. "We have to empathise that [Norrell] is a fish out of water. He's not comfortable in London society. Which was easy for me to do, because I feel the same. I go to dinners and I hope that people don't ask me too many questions that I don't know the answers to."

So if Norrell is all uptightness and discomfort, then Strange must be all blitheness and charm? Yes and no. The relationship between the two characters is the heart of the book. Their affection and bond, in spite of the almost catastrophic effect that their differences bring, is what drives the story. And in Marsan and Carvel, the producers have found, an at first glance unlikely, but ultimately brilliant duo in bringing Strange and Norrell to life. The cast also features Charlotte Riley as Arabella Strange, Paul Kaye as the street magician Vinculus, Enzo Cilenti as the enigmatic unbusiness-like man of business, Childermass, and Marc Warren as the gentleman with the thistledown hair. Jonathan Strange and Mr Norrell is a truly big production. And not forgetting the setting of 19th-century London, and all the costuming that requires, the misty moors of Yorkshire, and the eerie otherworldliness of Faerie. It's a story of friendship. It's an adventure. It's a romance. And it's magic.

So buy the book and read it quick. Then tune in. The magic extends through all the pages and onto the screen, and you'd best not miss it.

BBC 1, Sunday, 9pm