The 1911 census is a record of everyone who lived in England and Wales in 1911. The official UK 1911 census website, in association with The National Archives. Free index search with pay per view access to detailed information and images.
In the event of war a National Register was taken that listed the personal details of every civilian in England and Wales. The 1931 census was destroyed by fire. No census was taken in 1941 because of the war. So the 1939 register is the only national census-like resource available for this period. Findmypast has searchable indexes; database results and some digitized images are available with a fee-based subscription.
The St. Catherine's Marriage Index Includes selective transcriptions for South-East England, a complete transcription for the March Quarter of 1849 for all of England & Wales, and an ongoing transcription for the Year 1856.