Q: Where is Merlin at the beginning of series 4?
A: He starts the series in a happy place. He now knows Camelot like the back of his hand and can do everything with his eyes closed. Of course, he's not as talented a servant as he should be, but that's not his thing. Magic is his thing.

Q: So is he soon called upon to use his magic?
A: Absolutely. His magic powers are immediately challenged by the Dorocha. They are tortured spirits of the underworld. Morgana unleashes them, and they cause chaos in Camelot. They operate at night and can only be repelled by the light. If you find yourself alone in the dark with one, you are a goner. So a huge theme is the fear of the dark. Also Merlin's magic is useless against them. How does he cope without it?

Q: Morgana presents the greatest threat to Camelot in this series, then?
A: Yes. She is desperate to claim the throne, and the only person who stands in her way is Arthur. She's absolutely power hungry, fixated on regaining Camelot. You see within the first 10 minutes of the first episode just how ruthless she is. Why is she like that? At some points, I think even she doesn't know why. But that happens in life. People just want power. So Merlin has to provide a huge amount of help in Arthur's battle against Morgana. She is Merlin's ultimate enemy.

Q: Can you describe the state of Arthur and Merlin's relationship at the start of the fourth series?
A: They are master and servant, but they have also always been friends. They can't help but like each other for their own quirks. What is different this year is that you see a vulnerable Prince making use of Merlin as an adviser. For his part, Merlin realises how much he needs to be strong for Arthur's sake.

Q: Is Arthur still in the dark about Merlin's magical powers?
A: Yes. Arthur still has no idea about Merlin's magic. Fans always ask me, "why doesn't Merlin reveal his magic to Arthur?" But he'd be an absolute fool to do that. At the moment, Arthur is like his father, who created the rules banning magic. If Merlin revealed his power to Arthur now, he could risk everything. He needs to be 100% sure that the time is right. Merlin's dream is to live in a land where he can be free and ruled by the greatest king the world has ever known. It would be madness to risk that for the selfish reason of revealing himself now.

Q: Why has the series proved such an international hit?
A: They're just really good stories. They deal in universal themes such as good versus evil and the triumph of true love. They also appeal right across the generations. The fan base goes from 8 to 80. It's right across the board. There is no one who isn't touched by Merlin.

Q: Does it help that this is a new twist on an old classic?
A: Yes. People all over the world are familiar with the Arthurian legend, but the good thing about this show is that you're never sure how you will see it retold. From the very beginning, the story has been constantly retold – and now we're part of that very tradition. The other thing is that never before has it been seen in a fantasy setting like this. That opens doors to so many other avenues. In addition, viewers are really attached to the characters.

Q: Do fans often stop you in the street?
A: It does happen, but it's never unbearable. I've never had any nasty experiences – everyone is always so lovely to me. I can still buy a pint of milk. You can still do whatever you want, but there is always a chance now that it might not just be an anonymous shopping trip. People might notice you in a different way. Often they need convincing that I am who they think I am; they keep asking, "are you really Merlin?" All the time I'm thinking, "but I only want to buy a pint of milk!"

Q: Do you still get the same buzz as ever out of playing Merlin?
A: Definitely. It's a lot of hard work, but it always exciting and it always worthwhile. It would be a different story if you put so much effort into something and at the end of it all you thought, "why did I bother?" But when I finish filming a series of Merlin, I always think, "oh my God, I'm so delighted to have been part of this." We had a cast and crew screening recently, and at the end of that we all felt so lucky to be involved in this show. One crew member said, "I've never, ever been so proud to work on a show. I'm so happy to see my name in the credits." It really is something special!

http://ten.com.au/merlin-interview-with-colin-morgan.htm