 Clive Swift and Geoffrey Palmer have had previous roles in Doctor Who . Swift portrayed <unk> in Revelation of the Daleks , while Palmer played Undersecretary Masters in Doctor Who and the Silurians , and the Administrator in The Mutants . Jessica Martin had played Mags in The Greatest Show in the Galaxy . In addition , Bernard Cribbins played Tom Campbell in Daleks ' Invasion Earth : 2150 A.D. , the second Doctor Who feature @-@ film adaptation starring Peter Cushing as well as Arnold <unk> in the audio play Horror of Glam Rock . Colin McFarlane , who provided the voices of the Heavenly Host for the episode , went on to play General Pierce in Torchwood : Children of Earth , before later reappearing in Doctor Who as Moran in " Under the Lake " . 
