Fantasy drama series Merlin has been commissioned for a fourth run, it has been confirmed.

The BBC1 show stars Colin Morgan in the title role and features Anthony Head, Richard Wilson and John Hurt.

The third series has been pulling in audiences of six million on BBC1 each week.

Its current run will wind up with an edge-of-the-seat climax on December 4.

Ben Stephenson, the BBC’s controller of drama commissioning, said: “Merlin continues to perform outstandingly well against X Factor and offers audiences an alternative treat on Saturday nights.

“I’m pleased to confirm that the magical world of Camelot will be returning next year for a fourth series of this fresh and modern retelling of a classic British legend.”

Series three has seen a number of guest appearances including names such as Emilia Fox, Miriam Margolyes and Warwick Davies.

The new 10-part series will start filming in March.

The BBC said the drama has enjoyed huge international success, selling to 180 countries.