The information requested falls under the remit of the UK Statistics Authority.

Please see the letter attached from the National Statistician and Chief Executive of the UK Statistics Authority.

Professor Sir Ian Diamond | National Statistician

The Rt Hon. the Lord Blencathra

House of Lords

London

SW1A 0PW

1 May 2025

Dear Lord Blencathra,

As National Statistician and Chief Executive of the UK Statistics Authority, I am responding to your Parliamentary Question asking, following the decision of the Supreme Court in For Women Scotland Ltd v The Scottish Ministers [2025] UKSC 16 on 16 April, whether Census 2021 data will be reviewed and published based on male and female biological sex (HL6931).

Sex is a core demographic variable of fundamental importance for a range of census users providing vital information for national and local population statistics. In Census 2021 for England and Wales, as in all previous censuses, a binary sex question asked whether respondents were female or male. Supporting online guidance for this question from 9 March 2021 onwards stated, "If you are considering how to answer, use the sex recorded on your birth certificate or Gender Recognition Certificate.” This was changed on 9 March from guidance based on legal documents, following a court order[1].

The sex variable in Census 2021 data is based on the sex recorded by the person completing the sex question[2]. We cannot retrospectively change the basis on which those data were collected and defined, nor would it be possible to accurately derive a new ‘biological sex’ variable based on responses to one or more Census 2021 questions.

The Government Statistical Service (GSS) is currently prioritising work to develop new harmonised standards for data on sex and on gender identity. This will include providing guidance for official statistics producers on definitions, survey questions, suggested presentations, and information for data users. The new standards will be developed through rigorous research and testing with a range of users. It will also include learnings from the experience of other countries and their census data collections, as well as from the independent report published by the Department of Science Innovation and Technology, the Review of data, statistics and research on sex and gender[3]. This work will also take account of any relevant guidance issued by the UK Government following the Supreme Court ruling of 16 April.

Yours sincerely,

Professor Sir Ian Diamond

[1]https://www.ons.gov.uk/news/statementsandletters/updatedstatementoncensus2021sexquestionguidance

[2]https://www.ons.gov.uk/census/census2021dictionary/variablesbytopic/demographyvariablescensus2021/sex

[3]https://www.gov.uk/government/publications/independent-review-of-data-statistics-and-research-on-sex-and-gender

The information requested falls within the responsibility of the UK Statistics Authority. I have asked the Authority to reply.

The information requested falls within the responsibility of the UK Statistics Authority. I have asked the Authority to reply.

The information requested falls within the responsibility of the UK Statistics Authority. I have asked the Authority to reply.

The information requested falls within the responsibility of the UK Statistics Authority. I have asked the Authority to reply.

The information requested falls within the responsibility of the UK Statistics Authority. I have asked the authority to reply.

Letter from Glen Watson, Director General for ONS, to Lord Oakeshott, dated May 2013.

As Director General for the Office for National Statistics, I have been asked to reply to your recent Parliamentary Question concerning, what were the numbers of (1) women, and (2) men, employed in (a) central government, (b) local government, (c) the National Health Service, and (d) the police, (i) in June 2010, and (ii) at the latest date for which data are available; and what is their forecast of those figures for 2015. (HL42)

The Office for National Statistics is not able to produce numbers of women and men employed in central government, local government, the National Health Service and the police.

Figures for total employment in (a) central government, (b) local government, (c) the National Health Service, and (d) the police, (i) in June 2010, and (ii) at the latest date for which data are available, December 2012, can be found in the table below. Forecast figures are not available.

. English further education colleges and English sixth form college corporations classified to public sector from 1993 to 31 March 2012. They are therefore included in public sector estimates from 1993 to Ql 2012.². Data for the NHS are subject to revisions.³. Police (England and Wales) are based on projections and subject to revision.