Q: Context: The census in the United Kingdom is decennial, that is, held every ten years, although there is provision in the Census Act 1920 for a census to take place at intervals of five years or more. There have only been two occasions where the census has not been decennial: There was no census in 1941 due to the war; and a mini-census using a ten percent sample of the population was conducted on 24 April 1966. There are actually three separate censuses in the United Kingdom-in England and Wales, Scotland, and Northern Ireland, although they are often coordinated. From 1821 until 1911, the census included the whole of Ireland.

Question: how often do we have a census in the uk?
Let's give stream of consciousness below
To answer the question, consider the following: The census in the United Kingdom is decennial, that is, held every ten years, although there is provision in the Census Act 1920 for a census to take place at intervals of five years or more. So the answer is every ten years.