BBC1 revealed today a long-term commitment to mainstream family-orientated sitcom After You've Gone. The comedy, which stars Nicholas Lyndhurst and Celia Imrie as a battling father and mother-in-law, has now been commissioned through to at least the end of 2009.

A third series of eight episodes, plus a Christmas special has already in the works for a number of weeks. It is set to be broadcast in the autumn along with fellow returning BBC1 sitcoms The Green Green Grass and Not Going Out.

However, we now understand that acting BBC One controller Roly Keating and comedy commissioning controller Lucy Lumsden have now ordered an extended-length 2009 series as well. This fourth series will be made up of ten regular episodes, plus another Christmas special.

It is not a normal strategy to commission so many episodes of a British sitcom up-front. The only other BBC One sitcom to have been given a similar sized greenlight in recent years is My Family, that comedy currently has two series in production (series eight starts shortly). It is notable that both these shows have been created by Fred Barron using the American team-writing model, this allows more episodes to be written in a shorter space of time.

Kenton Allen, BBC Creative Head of Comedy Talent says: "American style team writing is now alive and kicking within BBC Comedy. This fantastic commitment to After You've Gone means we can now deliver family sitcom in consistent volume to BBC One with all the genuine benefits that team writing brings."

In 2007 there were sixteen episodes of After You've Gone - it became one of the first British sitcoms to return for a second series in the same year that it made its debut. The comedy regularly attracted audiences of over 5 million during its first two series.