Missing sketches from Peter Cook and Dudley Moore's 1960s BBC series Not Only... But Also... have been found.

40 years ago the BBC erased 13 out of 23 episodes of the duo's acclaimed sketch show. It was standard practice at the time to re-use the expensive videotape. Archivists have now announced the recovery of some of this material.

Channel 4 says: "Many of the sketches were thought to have been lost forever. However, a recent discovery by film archivists uncovered a number of sketches from the UK and Australia, some of which haven't been seen since they were first broadcast over fifty years ago."

Radio Times reports that among the sketches recovered are one of Moore performing on the piano, and two sketches of the double act in Australia; footage that has not been seen in the UK since the 1970s.

The discovered material will be shown in a new Channel 4 programme, Peter Cook & Dudley Moore: The Missing Sketches. As well as airing the newly found material, the programme will show classic clips and feature contributions from Not Only... But Also...'s producer Dick Clement; the duo's collaborator, Barry Humphries; and fans Richard Ayoade, Josie Lawrence and Ronnie Wood.

Speaking about the sketches, Dick Fiddy of the British Film Institute, says: "Pete and Dud are British comedy royalty. Any recovered material from them is a major cause of celebration."

The documentary's producer and director Richard Dean comments: "It's testament to their writing that these sketches have stood the test of time and I hope this documentary inspires a new generation of Peter Cook and Dudley Moore fans."

Channel 4's Helen Cooke added: "Channel 4 is hugely proud to be able to showcase and celebrate these precious finds and rediscover what made Pete and Dud so brilliant. The programme promises to be a celebratory look back at two irrepressible British comedy icons at the top of their game."

This new documentary will be shown just over one month on from The Undiscovered Peter Cook (iPlayer), a BBC Four documentary presenting never-before-seen material from Cook's career that was kept by his widow. Lin Cook died last week, and her funeral will take place tomorrow (Friday 9th December).

In 2010 BBC Two broadcast Pete And Dud: The Lost Sketches, a show in which Jonathan Ross looked at the legacy of the duo, with an ensemble of actors including Adrian Edmondson, Alistair McGowan, Hugh Dennis and Simon Day performing some of the erased Not Only... But Also... material in front of a studio audience.

Peter Cook & Dudley Moore: The Missing Sketches will be broadcast on Channel 4 on Saturday 31st December 2016 at 8pm.