Doctor Who
Missing episodes

Between 1967 and 1978, large amounts of older material stored in the BBC's various video tape and film libraries was either destroyed or wiped. This included many early episodes of Doctor Who, those stories featuring the first two Doctors: William Hartnell and Patrick Troughton. In all, 97 of 253 episodes produced during the programme's first six years are not held in the BBC's archives (most notably seasons 3, 4, and 5, from which 79 episodes are missing). In 1972, almost all episodes then made were known to exist at the BBC, while by 1978 the practice of wiping tapes and destroying "spare" film copies had been brought to a stop.

No 1960s episodes exist on their original videotapes (all surviving prints being film transfers), though some were transferred to film for editing before transmission and exist in their broadcast form.

Some episodes have been returned to the BBC from the archives of other countries that bought prints for broadcast or by private individuals who acquired them by various means. Early colour videotape recordings made off-air by fans have also been retrieved, as well as excerpts filmed from the television screen onto 8 mm cine film and clips that were shown on other programmes. Audio versions of all lost episodes exist from home viewers who made tape recordings of the show. Short clips from every story with the exception of Marco Polo (1964), " Mission to the Unknown " (1965) and The Massacre (1966) also exist.

In addition to these, there are off-screen photographs made by photographer John Cura, who was hired by various production personnel to document many of their programmes during the 1950s and 1960s, including Doctor Who. These have been used in fan reconstructions of the serials. The BBC has tolerated these amateur reconstructions, provided they are not sold for profit and are distributed as low-quality copies.

One of the most sought-after lost episodes is part four of the last William Hartnell serial, The Tenth Planet (1966), which ends with the First Doctor transforming into the Second. The only portion of this in existence, barring a few poor-quality silent 8 mm clips, is the few seconds of the regeneration scene, as it was shown on the children's magazine show Blue Peter. With the approval of the BBC, efforts are now underway to restore as many of the episodes as possible from the extant material.

"Official" reconstructions have also been released by the BBC on VHS, on MP3 CD-ROM, and as special features on DVD. The BBC, in conjunction with animation studio Cosgrove Hall, reconstructed the missing episodes 1 and 4 of The Invasion (1968), using remastered audio tracks and the comprehensive stage notes for the original filming, for the serial's DVD release in November 2006. The missing episodes of The Reign of Terror were animated by animation company Theta-Sigma, in collaboration with Big Finish, and became available for purchase in May 2013 through Amazon.com. Subsequent animations made in 2013 include The Tenth Planet, The Ice Warriors (1967) and The Moonbase (1967).

In April 2006, Blue Peter launched a challenge to find missing Doctor Who episodes with the promise of a full-scale Dalek model as a reward. In December 2011, it was announced that part 3 of Galaxy 4 (1965) and part 2 of The Underwater Menace (1967) had been returned to the BBC by a fan who had purchased them in the mid-1980s without realising that the BBC did not hold copies of them.

On 10 October 2013, the BBC announced that films of eleven episodes, including nine missing episodes, had been found in a Nigerian television relay station in Jos. Six of the eleven films discovered were the six-part serial The Enemy of the World (1968), from which all but the third episode had been missing. The remaining films were from another six-part serial, The Web of Fear (1968), and included the previously missing episodes 2, 4, 5 and 6. Episode 3 of The Web of Fear is still missing.
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