As an empire, Britain collected a vast array of statistics about its domestic and colonial affairs. An excellent source, not to be overlooked, is the Parliamentary Papers series Location: Documents (Lamont) Br Doc 650, which contains early censuses, trade and navigation reports, statistics on fisheries, labor statistics, British India, and statistics on many more topics. More information about Parliamentary Papers can be found at the Parliament tab of this guide.

Also notable are

Abstract of British historical statistics, by B. R. Mitchell. 1971
Location: Documents (Lamont) Br Doc 152.26

Annual abstract of statistics
Location: Documents (Lamont) Br Doc
152. 10

UK National Statistics is the official United Kingdom statistics site.