Siobhan Finneran has left Downton Abbey and will not appear as dastardly maid Sarah O'Brien in this year's fourth series, the actress herself has announced. 

"I’m not doing any more," Finneran told The Mirror, adding: "O’Brien is a thoroughly despicable human being - that was great to play.”

It is understood that O'Brien's absence will be explained in the first episode of series four and the character will not be killed off.

Finneran's departure follows that of Dan Stevens, whose character Matthew Crawley died in last year's Christmas special, and Jessica Brown-Findlay, whose screen death provided the major shock of series three.

Downton Abbey series four is filming now for broadcast on ITV later in 2013.

Siobhan Finneran: "O'Brien with a boyfriend would be stupendous!"

Rob James-Collier and Siobhan Finneran on Thomas and O'Brien's series three bust-up

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