Guest Stars Alex Kingston as Professor River Song Frances Barber as Madame Kovarian Marnix Van Den Broeke as The Silent Sydney Wade as Little Girl Stuart Milligan as President Richard Nixon Mark Sheppard as Canton Delaware Chukwudi Iwuji as Agent Carl Peterson Mark Griffin as Phil Glenn Wrage as Gardner Tommy Campbell as Sergeant Ishem Kerry Shale as Doctor Renfrew Jeff Mash as Grant Ricky Fearon as Tramp Peter Banks as Doctor Shepherd