Merlin: Casting a magic spell on viewers

Walking down a narrow track, deep into the Forest of Dean, the cloudless, blue sky slowly becomes obscured as the trees grow ever denser. A light mist weaves its way around the ancient trunks inducing an air of magic and mystery.

It seems only fitting then to find two characters of folklore, Merlin and Morgana, deep in conversation at the end of the path, their silhouettes highlighted by a stream of golden sunlight breaking through the trees.

Then a cry of "Cut" can be heard and, in an instant, the fantastical atmosphere is broken as crew members set about preparing the next scene of the successful TV series, Merlin.

In a spin on the legend of Camelot, Merlin, now in its third series, is based on Arthur and Merlin in their formative years, with Merlin a novice wizard and king-to-be Arthur.

"There's a danger with fantasy that people take the light-hearted approach, but I think you can put a lot of heart and emotion into it," says Colin Morgan, who plays Merlin.

"I think it's important to put a 100 per cent into everything and find new ways to make it believable," adds the 24-year-old, who hails from Northern Ireland.

As a wizard in training, Merlin spends a lot of time casting spells but Morgan says it's only now he's getting to grips with the complicated pronunciation.

"When we first started out it was a bit daunting," he says. "It's great because they're in genuine old English so whenever I get the gobbledegook," he says, referring to the script, "I find out the meaning, and then the phonetic pronunciation. So when I say the spells, I genuinely know what they mean."

Though Morgan spends most of his time dramatically casting spells with no idea how they'll look on-screen when the special effects are added, he says it's "no excuse not to go for it".

"You have to not feel silly doing things," he says. "It's going to look stupid if you feel stupid."

At this point his co-star, the blonde and perpetually pouting Bradley James, left, who plays Arthur, walks over looking a little constrained in head-to-toe chain mail.

"I'm prepared to lose a stone in sweat in each day," says Devon-born James, 26, of his heavy costume. "It's a small price to pay because, in my mind, I get to play the best character in the show."

You suspect by Morgan's reaction - mock eyes to heaven - he's heard this before, but then their on-screen chemistry is plain to see off-screen, too.

Although the pair are now the heroes of a big Saturday night show, so far they've had rather less impact on the public at large.

"Colin has a magic beanie hat that prevents him from being recognised," says James straight-faced. "If we go out, he'll put the magic hat on and I'll stand there and people will go, 'You're the bloke from Robin Hood' to which I'll go, 'No, I'm not'. Then it'll be, 'Sorry, Merlin' and they'll talk to me. Then I'll go, 'You see him?' and they'll look Colin square in the eyes and won't recognise him!"

Morgan laughs, adding it's mostly kids that know who he is. "I'm always asked, 'How do you do the magic?' and you can't very well turn round to a five-year-old and say, 'It's done with CGI in London'."

The new series is already proving the darkest yet.

"The characters are more mature and the story feels more complicated," says Morgan.

Many aspects have remained the same. For one, Merlin is still not allowed to use a sword with gusto, much to Morgan's chagrin, and Arthur still has no idea it's the wizard who's forever saving the day.

"I think the creators are really happy to milk that one and continue the line of Merlin saving the day behind Arthur's back," says James. "I think once you lose that dynamic, the show will change."

Then, of course, there are Arthur's purely gratuitous, shirtless scenes.

"It's not something I go, 'Great, there's a chance to take my shirt off' but at the same time, I'm not nave enough to think it's not something that people look for in the show," says James.

"All shows have a target audience and part of ours would get a kick out of that."

As for the rather more lean Merlin showing off his muscles, Morgan jokes, "They never ask me, do they? I don't know why that is!"

Top or no top, both receive hundreds of letters from fans from all over the world. "Mine are a bit intense," says James. "I get a lot from people of a certain age and mindset saying I'm their soulmate. I think they get confused and see a blonde hair, blue-eyed guy saving a kingdom," he adds. "The anti-climax would be phenomenal!"

Morgan also receives some "unusual things" but most of the time it's "really young kids who ask me to wave to them on the next episode".

Merlin continues tonight, BBC One, 7.05pm