If Colin Morgan is tired of talking about his role playing the most famous wizard in history, it does not show.

The BBC's fantasy series, Merlin, showing here on Prime, has been confirmed for a fifth season, which means the young actor gets a break before heading back to the wilds of Wales.

"I still love it," Morgan says in his Northern Irish accent. "We finished the fourth season about a month ago and I remember looking at the clapper board and thinking, `I'm actually standing on a set filming a TV show called Merlin'. I don't take the job for granted and I don't ever want to get complacent about the role."

Based loosely on Arthurian legend, the show revolves around a young Merlin – played by the 25-year-old, impish-looking Morgan – who must keep his powers hidden until his contemporary, Arthur Pendragon, who is a newly minted King of Camelot (Bradley James), becomes a wise leader.

Add to the mix Guinevere (Angel Coulby), who is sensible and feisty, and Morgana (Katie McGrath), a powerful sorceress who is doing her best to undermine them all. Not to mention a CGI dragon voiced by John Hurt, sword fights and enough chaste kisses, back-stabbing, spells and intrigue to keep everyone from 10 to 80 happy.

But Merlin was no overnight success. When it first aired in Britain in 2008, ratings were low. Over the past couple of years, and with a change of network, the show has found its niche. Morgan says the enduring legend has helped Merlin to survive.

"Although it's a story that has been retold over thousands of years, it's never been told like this, with the fantasy elements. I do feel like I'm part of a legacy."

Morgan came late to the legend. He did not, for instance, hear stories about Lancelot and King Arthur while growing up in Northern Ireland.

His first encounter with Merlin, he says, was Walt Disney's animated version of The Sword and the Stone.

But today, after thousands of encounters with hardcore fans and some extra reading, Morgan laughs, "I'm not saying I could lecture [on the subject] at a university but I can hold my own ... for a little while."

Although they can be intense, he says he finds meeting fans of the show one of the joys of his job.

"It's really exciting. I'm usually locked up in a shack in Wales for eight months of the year, so to get out and see what people think of the show is fantastic. We've really tried to challenge ourselves as actors and deliver great stories."

When pressed about some of the downsides of working on the show, he is quick to cite the Welsh weather.

"When you've been shooting in a forest and it's been raining for five days straight, that's hard. Not so much for the actors, but I feel sorry for the crew," he says.

The long days on set can also take their toll, especially when Morgan is filming up to nine different episodes, each with a different director, cast and crew.

"Sometimes I get confused, I forget my own name – but I love what I do. I feel like we all have a torch to carry and as long as we have the support, long may that torch burn."

What: Merlin When: Friday, 8.35pm Where: Prime