Mrs. Peel, we're needed.
Peter Capaldi as the Patrician.
There's a lot of roles in this show that would be perfect for Doctor Who stars. How about John Barrowman as Carrot? Or Freema Agyeman as Angua?m
He’d be good. He’d be very good.
But if I’m casting an ex doctor it’s got to be Tennant. He’s done enough villains now that he’s got an Oh Shit aura when he’s on the screen being even vaguely menacing, and he can get the Vetinari Snark in too, while still being basically a good ruler.