Debbie Horsfield Only Had One Man In Mind To Play Her 'Poldark'

*Warning: This episode contains spoilers for Episode One of Season Four of *Poldark.

Debbie Horsfield is the only writer of every episode of MASTERPIECE’s Poldark, so she definitely knows what’s on the horizon in the series’ fourth season. Secrets, lies and parliamentary politics come to Cornwall in a big way this season. Horsfield — who is also one of the series' executive producers — offers a sneak preview of the surprises still to come, and reveals why Aidan Turner was always the only actor she would cast as Ross.