Following the surprised reaction by Downton Abbey fans to the show’s Christmas special, writer Julian Fellowes has explained the cliff-hanger. Warning: Spoiler alert!

In an interview with The Daily Telegraph, Fellowes said that he felt he had no choice but to kill off the character of Matthew Crawley, played by Dan Stevens, who died in a car accident in the show.

He said: "We would have loved to keep him. We would have loved to keep Jessica [Brown Findlay, who played Lady Sybil Crawley] too.

"We have always tried to persuade him to stay. He had done fantastically well for the series and his creation of Matthew was terrific.

"But this is life. Dan felt that this was right thing for him, and the right moment to move on to different areas."

He added: "If he had been prepared to come back for maybe two or three episodes in a series, that would be different. Then we could have had a foreign posting or invented a career that would have made it possible for him to be away.

"Otherwise we would have had to make this tremendously successful love affair between Mary and Matthew unhappy, which I didn't feel would be believable.

"For them to then separate and Matthew never set eyes on his son again would not be believable either."

He added: "We didn't really have any option. By him dying, their love can remain in tact."

Instead of roaming the halls of Downton Abbey, Stevens can now be seen on stage in The Heiress in New York until February.