In 1851 "Britain" was properly called The United Kingdom of Great Britain and Ireland.

The total reported population of the United Kingdom at the time of the 1911 census was 37,328,034 persons. This census consisted of both England and Wales.

Census are taken in the United Kingdom for population counts and tax purposes. The United Kingdom uses the census information to prepare for tax rates and population counts.

R. A. F. Page has written:

'Census of Norwich, 1851' -- subject(s): Census, 1851, Genealogy

In the modern sense, the first Census was in 1801.

It could be said that the Domesday Book, compiled in 1086, was a kind of Census.