The continued closure of the census from 1911 to the 2001 census is totally ludicrous. In this day and age it is perfectly possible to withold any sensitive information but at the same time release the bulk of the information.
One could even make a case for saying the witholding of census information is racist.
Why?
Because the information given by aliens is available on line (National Archives website) and that holds more sensitive information than the census
"Aliens Registration Cards (1876 - 1991)
The information provided on the cards includes full name, date of birth, date of arrival into the UK, marital status, details of any children, address, employment history (including employer's name and address), and date of naturalisation with the Home Office reference if applicable. The cards usually include at least one photograph and for most cases there are continuation cards .
A registered person was required also to register any changes of name, address, marital status, nationality, and employment or occupation. Penalties seem to have varied for not notifying the police of changes to personal circumstances, increasing if they re-offended. That said, the majority of aliens were not fined for misdemeanours. "
The cards even show the misdemeanours
Cheers
Guy