In the next couple of years we will, hopefully, have access to the 1921 census for England, Scotland and Wales. Sadly, there will be none for any part of Ireland because, in that year, there was major political changes which precluded the taking of a census. In 1926 there were two census for Ireland – one for the new Irish Free State and one for Northern Ireland. The lack of a 1921 census for Ireland is a cause for regret among family historians. The release date for the two 1926 census is likely to be 2026, although there has been some pressure for an earlier release in the Republic of Ireland. Some preliminary general documents for the 1926 Northern Ireland census have recently been released
https://www.nisra.gov.uk/publications/1926-census-reports