Before receiving the film for classification the BBFC was sent a script on 1 February 1965. Our archive document is a BBFC examiner's report on the presented script. By the time the BBFC examiners received the script, at least 50 episodes of the television programme had been broadcast by the BBC, and our examiner notes "I think most children in this country are now familiar with Dr. Who". With an established audience it is perhaps unsurprising that the production company sought a U certificate.
The examiner's notes detail the elements of the script that could have potentially raised issues for classification at U. The infamous Daleks - described as "rather like large-size pepper-pots" - are less of a concern than the quantity of terrified screaming. In a letter summarising the points made in the report, BBFC Director John Trevelyan explains "In U films we are always anxious not to have shots of people who are terrified, particularly close shots", and " We are always worried about screams for the U category....In view of this you should take a lot of care with your soundtrack."
The BBFC report notes that the film was to be presented in colour, potentially making the film more suitable for a family audience. This is contrary to some horror films of the period, for which examiners sometimes argued that colour presentation heightened the effect of the horrific scenes and therefore required a higher age category.
There are references in the report to Doctor Who being a 'C' programme, and we can perhaps assume this relates to Children's Hour, the 5pm-6pm BBC timeslot dedicated to family viewing from 1922-1964.
The completed Dr. Who and the Daleks was submitted for classification in June 1965, and given a U, uncut. The film has been a U certificate on video and DVD since, and was again rated U for theatrical release in 2013.