Stephen Merchant celebrates the writing partnership of Ray Galton and Alan Simpson, the ground-breaking duo who brought social realism to British comedy and helped form the foundations for modern-day classics such as The Office, Peep Show and The Thick Of It.

After meeting in a tuberculosis sanatorium in 1949, the pair started writing for the hospital's radio station and within two years they were writing for the UK's top comic talent. In a move that changed comedy for ever, the pair insisted that comedy should not be interrupted by howling crooners, whistling hillbillies or harmonica players, but instead should reflect life as it is. The show they created, Hancock's Half Hour, was so popular that pubs and shops complained that it was causing them to lose business.

They followed up Hancock's Half Hour with Steptoe And Son, which proved a huge hit gaining 28 million viewers. However, the series was not without controversy: the episode The Piano provoked complaints from Mary Whitehouse and even lead to questions being asked in the House of Commons.

The pair also wrote for a who's who of comedy, including Frankie Howerd, Peter Sellers, Arthur Lowe, Warren Mitchell and Les Dawson. While the pair effectively disbanded in 1978, their work is still immensely important and performed around the world today.

As well as the writers themselves, contributors to the documentary include David Mitchell, Ben Elton, Denis Norden and Damaris Hayman. Archive interviewees include Tony Hancock, Sid James and Harry H Corbett.