Game of Thrones story editor Bryan Cogman has promised more murder and mayhem in future seasons of the show.

He also told SciFiNow that George RR Martin's novel A Storm of Swords will "more or less" form the basis of the HBO drama's third and fourth seasons.

"We get more and more amazing cast members every year and we kill a few too to make room, and that tradition is going to continue in season three," he said.

"More or less we're covering seasons three and four with the events of A Storm of Swords but from now on we're not looking at a book per season, there's going to be a lot more blending of elements of all the books as needed.

"It was impossible for us to conceive stuffing all of the major events of Storm of Swords into ten episodes and the schedule is such that we really can't fit in more than ten episodes per season," he he added.

Game of Thrones season three will debut on Monday April 1st on Sky Atlantic.