Page "Census in the United Kingdom" Paragraph 15

On 24 April 1966, the UK trialled an alternative method of enumeration-long form / short form.

Every household was given a short form to complete, while a sample of the population was given a long form to collect more detail.

The short form was used for the population count and to collect basic information such as usual address, sex, age and relationships to other household members.

This was the first and only time that a five-yearly census was carried out in the UK.