The death of Adric's brother Varsh hit close to home for Matthew Waterhouse. Two years prior, Waterhouse's older brother Nicholas committed suicide.
Richard Willis (Varsh) and June Page (Keara) met and fell in love during the making of this serial. They later married although they were divorced some time before 1993. In 1993, Richard married Kate O'Mara who also appeared in Doctor Who as evil Timelady The Rani. They divorced in 1996. In 1998 he married Lori Fox and divorced her in 2002. He has been married to his 4th wife Heidi Reimer since 2007 and currently resides in the USA. (Information correct as of March 2019)
This episode was watched by 5.5 million viewers on its original transmission.
When the Marshmen start coming through the various outer hatches of the Starliner (three of the hatches are shown), it is obviously the same Marshmen coming through the same hatches - done to save money.