There was no official census in 1941 because of the war - the only census that has been missed since they began in 1801 - but the National Registration Act, passed on September 5 1939, resulted in a nationwide enumeration that was seen as a virtual substitute, though it was taken principally for the purposes of facilitating National Service callup, providing manpower and general population statistics, and
facilitating proof of identity for the purposes of claims for allowances and issuing food ration cards.
The actual registration day was September 29th and the forms were collected nationally by enumerators the next day. However, serving members of the armed forces were excluded unless on leave and spending the night in a private house or hotel.
It has been helpful to a certain extent in confirming exisiting information, but on the whole it is a disappointment mainly due to the fact records of people younger than 100 and still alive, or who died after 1991 are officially closed.
As you can see from this example
The householder at no 10 was in the Metropolitan Police War Reserve which was a source of concern after the war!!