Ian Collier (25 January 1943-1 October 2008[1]) appeared in two Doctor Who television stories: as Stuart Hyde in The Time Monster and Omega in Arc of Infinity. He reprised the role of Omega in Big Finish Productions' Omega. He also played Commissar Sallis in Big Finish Productions' Excelis Decays and Isaac Summerfield in Big Finish's Bernice Summerfield series.