List of incomplete Doctor Who serials

There are numerous portions of the long-running British science-fiction television programme Doctor Who that are no longer held by the BBC. Between 1967 and 1978 the BBC routinely deleted archive programmes, for various practical reasons (lack of space, scarcity of materials, a lack of rebroadcast rights). As a result of the cull, 97 of 253 episodes from the programme's first six years are currently missing, primarily from seasons 3 through 5, leaving 26 serials incomplete. Many more were considered lost until recovered from various sources, mostly overseas broadcasters.

Doctor Who is not unique in its losses, as many broadcasters regularly cleared their archives in this manner. Until the BBC changed its archiving policy in 1978, thousands of hours of programming, in all genres, were deleted. Other affected BBC series include Dad's Army, Z-Cars, The Wednesday Play, Steptoe and Son, and Not Only... But Also.ITV regional franchises also deleted many programmes, including early videotaped episodes of The Avengers.

Doctor Who is unusual, however, in that each of its 97 missing episodes survives in audio form, recorded off-air by fans at home. Most episodes are also represented by stills or short video clips. Furthermore, after careful restoration, all 1970s episodes exist in full colour, which is not always the case for other series.

Efforts to locate missing episodes continue, both by the BBC and by fans of the series. Recovered episodes have been extensively restored for release on VHS and DVD; surviving soundtracks have been released on cassette and CD. Many missing episodes have had their visuals reconstructed, either through specially commissioned animation or use of surviving footage and photographs.

Between approximately 1967 and 1978, large quantities of videotape and film stored in the BBC's Engineering department and film libraries, respectively, were wiped or destroyed to make way for newer programmes. This happened for several reasons, primarily the belief that there was no practical value to its retention.

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