Peter O'Brien

Peter O'Brien played Ed Gold in the Doctor Who story The Waters of Mars.

He worked with Russell T Davies before in Queer As Folk, where his character was dating a main character who was a Doctor Who fan. When the main character was wondering whether to break up with him or not, he asked him to name all the (then 8) actors to play Doctor Who. He only named Tom Baker and Jon Pertwee and alluded to William Hartnell (the guy with the grey hair) and Peter Davison (the vet).