oops! Forgot to add this:
Relevant to prisons and the 2021 Census:
3.7 The census will also enumerate all people resident on the census date in communal establishments such as hospitals, nursing and residential homes, and hotels. Special arrangements will be made to enumerate residents in prison service establishments and immigration detention centres, on ships in ports and in military camps, and other population groups not resident in private households, such as persons travelling with fairs.
4.45 The census must reflect the lives of people living in communal establishments (such as hotels, hospitals, boarding schools, or prisons) as well as households. Methods of reaching such people will differ depending on the size of establishment and the varying levels of difficulty involved in making contact and ensuring that residents complete their returns. In some types of CE, individual paper questionnaires will be completed by residents. In others specific arrangements will be made following initial contact with the local authority or other managing agency about the level of support needed, and the most appropriate method of completion. CE follow-up will be conducted by census field staff who will receive appropriate training for the role.
It will be interesting to see how many Male prisoners select other than Male "Gender". The Gender question is voluntary though.
(Male prisoners with a GRC would, of course, answer F to the "sex" question).
assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/765089/Census2021WhitePaper.pdf