Gordon Jackson and his wife, actress Rona Anderson, photographed in the mid-1970s. During his life, Jackson starred in more than 80 feature films but Mr Hudson was probably his most famous role.

Gordon Jackson (left) wins a 1975 Variety Club award for his role as Mr Hudson. Also shown (l-r): Bruce Forsyth, playwright Simon Gray, David Jacobs, Esther Rantzen and Alan Bates.

Simon Williams photographed in the mid-1970s with his wife, actress Belinda Carroll. Though the marriage ended in the late 1970s, the relationship produced two children – Tam and Amy – who have both followed their parents into the acting profession. Simon later married another actress, Lucy Fleming.

David Langton played Richard Bellamy, master of 165 Eaton Place, from the first episode to the last. Langton (real name Basil Muir Langton-Dodds) had been working in theatre since he was 16, but his role as Richard, which made him a household face, came later, when he was aged 58. During some of the recording of UpDown, Langton lived at number 74 Eaton Place, right near number 65 which was used in the show.

A rare shot of Rachel Gurney, right, out of her Lady Marjorie costume and wig. She is surrounded by Freddy Shaughnessy, David Langton and Lesley-Anne Down at a special fête at Ringwold House in 1975 to mark the end of the series.

Rachel Gurney (Lady Marjorie) rehearsing on set. Gurney had been on the air as early as 1938 when she, aged 18, took part in a radio production of Elsie T Schauffler's political play Parnell as part of her membership of The Liverpool Rep.

Angela Baddeley and Evin Crowley during a dress rehearsal for A Cry for Help. Note that Baddeley is not wearing her usual Mrs Bridges wig and is crumbling thin air!

Angela Baddeley in Make-up being fitted with her Mrs Bridges wig. Baddeley's earliest traceable broadcast seems to have been a monologue called The Public Call Box on BBC radio in March 1927. So, while Mrs B was being scandalised by Frederick's behaviour in the UD episode Alberto, the real Angela Baddeley had already made her first broadcast; UpDown could have had a scene where Mrs B listened to Angela Baddeley on the radio. There's something to think about.