The show originated as an idea by actress friends Jean Marsh and Eileen Atkins for a comedy titled Behind the Green Baize Door, focused on two housemaids in a Victorian country house.

The concept dropped its comedy element and moved to Edwardian London under the title Below Stairs, and was offered first to Granada Television, which declined because it already had a period drama, A Family at War, in the works.

The programme went through several working titles, including Two Little Maids in Town, The Servants' Hall, That House in Eaton Square, and 165 Eaton Place, before John Hawkesworth suggested the final title Upstairs, Downstairs just before the first episode was produced.

Honor Blackman was shortlisted for the role of Lady Marjorie and George Cole for the butler Hudson, but Cole was dropped after it was decided a Londoner couldn't convincingly play a Scotsman, so Gordon Jackson was cast instead.

Eileen Atkins was originally slated to play maid Sarah Moffat opposite Jean Marsh's Rose, but she was busy playing Elizabeth I in the stage play Vivat! Vivat Regina!, so Pauline Collins took the role instead.

Due to an industrial dispute over extra pay for using new colour equipment, the first six episodes of series one were shot in black-and-white, and once colour resumed the first episode was remade in colour; the original black-and-white version is believed to have been wiped.

The exterior shots of the fictional 165 Eaton Place were actually filmed at 65 Eaton Place, with a '1' painted onto the building's number.

The theme tune, titled The Edwardians, was composed by Alexander Faris and won an Ivor Novello Award; part of it was reworked into the song 'What Are We Going to Do with Uncle Arthur?', performed in-story by Sarah Moffat and released as a single by Pauline Collins in 1973.

Upstairs, Downstairs won two BAFTA awards, three Writers Guild Awards, eight Emmys and a Golden Globe, and was ranked number 79 on the Writers Guild of America's 2013 list of the 101 Best Written TV Series.

Plans for a spin-off following Hudson, Mrs Bridges and Ruby running their seaside boarding house were abandoned following the death of actress Angela Baddeley in February 1976, though a different spin-off, Thomas & Sarah, did air in 1979.