The census is a once-in-a-decade count of the UK population. It collects detailed information about demographics, employment and housing.

Initial census results have now been published for England, Wales and Northern Ireland – showing the largest population recorded so far in each nation.

In this Insight, we explore what we know so far and the timetable for more detailed data releases.

When was the census carried out?

A census for England and Wales was carried out by the Office for National Statistics (ONS) in March 2021, and at the same time by the Northern Ireland Statistics and Research Agency (NISRA) for Northern Ireland. The Scottish Government decided to delay the census in Scotland by a year because of operational problems caused by the Covid-19 pandemic. Scotland’s census took place in March 2022.

What census data has been published so far?

The ONS has published data on the population by age and sex for local authorities in England and Wales. NISRA also published data in May 2022 on the population of Northern Ireland by age and sex.

The population of England and Wales on 21 March 2021 was 59.6 million, an increase of 6.3% compared with the 2011 Census.

The population of England was 56.5 million and the population of Wales was 3.1 million. Northern Ireland’s population on the same date was 1.9 million. In total, the population across all three nations was 61.5 million.

The graphic below shows how the population has changed since 2011 in different areas and age groups.

The East of England had more population growth between 2011 and 2021 than any other region or nation, with growth of 8.3%, followed by the South West (7.8%) and London (7.7%). The population of Wales grew the least, by 1.4%.

The census results also show an ageing population. The number of over-65s grew by considerably more than the number of children and teenagers, or the number of people aged 20-64.

An infographic showing how the population changed between the 2011 and 2021 censuses. The population grew most in the East of England, East Midlands, and South West England, and grew least in Wales. The population aged 65+ has grown the most. The 0-19 year old population is growing less, and fell in Wales and Northern Ireland. Growth in the 20-64 year old population is also relatively low.

The ONS’s statistical release includes data on population change at local authority level. The population decreased between 2011 and 2021 in some local authority areas, including in Kensington and Chelsea, Westminster, and several local authorities in North and West Wales.

How accurate is the census data?

Response rates to the census were high, with forms completed by an estimated 97% of households in England, Wales and Northern Ireland. The ONS’s target for England and Wales was 94%.

Covid-19 restrictions were still in place in March 2021, which led to concerns about whether the census data will show things as they typically are.

A blog post from the Centre for Cities called for the census to be delayed in 2021, arguing short-term changes in commuting patterns, students’ places of residence, and migration would distort census results and “skew a number of important administrative decisions”.

The ONS published a statement on its decision to go ahead with a census in 2021, explaining it factored the length and cost of a delay into its decision.

It acknowledges in the census data release that the pandemic “may have affected some people’s choice of usual residence on Census Day, for example, students and in some urban areas.” Some of these changes will only have been temporary reactions to Covid-19 restrictions, making the census results less representative of where these people typically live.

When will more detailed census data be published?

The ONS will publish ‘topic summaries’ for England and Wales between October and December 2022. These will be tables for single census variables, grouped by theme and released in stages.

These include characteristics like ethnic group, religion, and nationality; employment and housing status; and health and education. The 2021 census also asked for the first time about sexual orientation and (in England and Wales) gender identity and Armed Forces veterans.

Initially, this data will be available for local authorities and for small census areas (called Output Areas, Lower Super Output Areas, and Middle Super Output Areas). This will be followed by data for other geographical areas, including parliamentary constituencies.

NISRA will also publish topic summaries over a similar time period. These will only have statistics for local government districts and Northern Ireland overall. Data for other geographical areas will be available in summer 2023.

ONS and NISRA will next publish tables that break down the data by more than one variable at a time. This will happen in late 2022 and early 2023 for England and Wales, and spring 2023 for Northern Ireland.

When will census data for the whole UK be available?

In previous decades, the ONS has compiled and published UK-wide statistics from each of the three censuses.

This time, the process is complicated by the fact that Scotland’s census is being taken a year later than the other UK censuses.

ONS has said this “will impact the comparability of UK wide census data”, but it is working with NISRA and NRS to “provide, where possible, access to comparable data from across the UK that best support the information needs of users”.

NRS has not yet published a detailed outline of when it will publish Scotland’s census results, but has said that publication will start in 2023.

Further reading


About the author: Cassie Barton is a statistician at the House of Commons Library, specialising in demography and the census.

Photo by Flow Clark on Unsplash

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