Howmerlin has changed. When the fantasy- adventure series started in 2008 it was a Robin Hood- style kids’ romp filled with action and fire- breathing dragons. Much like the Harry Potter movies, Merlin has become progressively darker. Q. Did you ever think the show would be this successful? A. I don’t think anyone thought it would end up where it has. That’s not to say we didn’t believe in the stories. Five years is a hard thing to imagine for any commitment. The fan base is growing bigger across the world. Q. How has the Merlin character changed? A. It was always going to be a tale of growing up for Merlin. How does he become the great wizard that we know from the legends? Merlin is the one who is most lost among everyone. That is because the one thing he loves [ magic] is the one thing he cannot do [ because it is outlawed] in Camelot. We have seen him go from a naive boy who trusted in people a little bit too much to now having gained wisdom, power and strength. We’re seeing him grow into a young man. The same thing has happened with Arthur, who has just become king. This is the biggest step but it has happened in the wrong way. Arthur’s father died by magic, which is not what Merlin wanted at all. Now there are higher stakes. Everything could be lost. Q. The show centres on the relationship between Merlin and Arthur. How do you get on with your co- star Bradley James? A. We were all new when we started this show so we were all embarking on this adventure together. Bradley and I were always going to have a lot of scenes together. We have a great rapport. The tone of the show has changed, especially in series three when Morgana [ Katie Mcgrath] became a villain. I think the series is at its strongest when it goes a little bit darker. Q. Morgana seems to hate Camelot even more in the current series. A. One of Merlin’s big things is using your powers for the right reasons. Morgana is the perfect example of how things can go so badly wrong. It is a great shift for Katie’s character and she does it perfectly.