Ritchie has a small role in a fictional 1988 Doctor Who (1963) serial "Regression of the Daleks". This is a tribute to Dursley McLinden, who played Sgt. Mike Smith in the 1988 serial "Remembrance of the Daleks". McLinden died of AIDS on August 7, 1995 at the age of 30.
On Ritchie's wall there is a poster for Sir Richard Eyre's acclaimed 1982 production of 'Guys And Dolls' at the National Theatre which starred Ian Charleson. Charleson was diagnosed with HIV/AIDS in 1986 and died in 1990 aged 40. He asked that his cause of death be announced to raise awareness of the illness and was the first celebrity death in Britain openly attributed to AIDS.
This episode includes a scene featuring the Daleks. It's a Sin's creator Russell T. Davies was previously the showrunner of Doctor Who (2005).