This is a statement of agreement between the National Statistician, the Registrars General for Scotland and Northern Ireland, and the Chief Statisticians of Scotland and Wales. Similar agreements made for the 2011 and 2021 Censuses enhanced the extent of harmonisation across the UK. (It is noted that the Registrar General for Northern Ireland is also the Chief Statistician of Northern Ireland).

The National Statistician, Chief Statisticians and Registrars General, along with their organisations (including the census offices) all have a role in producing population and social statistics for the different parts of the UK. Each census office and administration has its own responsibility to research and make decisions on the future of its census and population statistics. This agreement aims to build on longstanding cross-UK cooperation in this area, throughout this complex period of transformation.


Final recommendations and decisions on the future of the census in the different parts of the UK will lie with the National Statistician, the Registrars General, and the respective ministers.
In the context of the autonomy of the relevant parties, the National Statistician, Registrars General and Chief Statisticians agree that they will aim to work in unison to ensure that high quality population, migration, housing and social statistics for the UK continue to be produced, with the objective of meeting the needs of data users and reflecting UN-ECE and other international best practise.

In particular, the National Statistician, Chief Statisticians and Registrars General have agreed that their organisations (including the census offices) will work together to reach consensus wherever possible on the areas for cooperation described in this statement of agreement, which will facilitate harmonisation where it is in the interest of the users of UK population and social statistics, and the public good more generally.

UK & international requirements

The production of population and social statistics in the UK is governed by, inter alia, the Statistics and Registration Services Act 2007, the Census Act 1920 and the Census Act (Northern Ireland) 1969, and any subsequent secondary legislation to the above.

In addition, there is a user demand for consistent, coherent and accessible statistics for the UK, for each country and geographic areas within each country. This need is recognised in the Code of Practice for Statistics, and commitments on joint working to fulfil the need have been made in the Concordat on Statistics. This agreement operates in the context of the Concordat as described in its 39th paragraph.

UN-ECE and the Statistics Division of the UN Department for Economic and Social Affairs have provided recommendations, principles and guidelines for population censuses in the UN-ECE region, which aim to improve the comparability of census at the UN regional level. The UN-ECE recommendations identify suggested core census topics and seek to facilitate the harmonisation of definitions, classifications and concepts. Censuses in UN-ECE countries are expected to follow the UN Fundamental Principles of Official Statistics.

Areas for cooperation

The National Statistician, Registrars General and Chief Statisticians have agreed the following areas for cooperation.

Maximising the harmonisation of inputs, methods, and outputs

1. The parties of this agreement commit to mutual support in the acquisition from third parties of administrative data for statistical purposes, where these data are of common interest, through:

    • sharing of lessons learned in data acquisition from specific suppliers;
    • onward sharing of data, with the agreement of the supplier; and
    • jointly negotiating data-sharing agreements for multiple parties concurrently.

Where data collected by one administration are of interest to a party in a different administration for producing statistics in scope of this agreement, support will be offered in the acquisition of these data by the relevant parties, through mediation with the data owner.
Action taken under this section will be consistent with paragraph 26 of the Concordat on Statistics, specifically its provisions on privacy and security guidelines.

2. The parties will continue to work together on cross-border data-sharing required to produce population and internal migration statistics. Where requirements change over time in order to support more frequent and timely estimates, the parties will negotiate to meet these requirements. Where new requirements cause disproportionate burden on a party, discussions may be held around cost-sharing, as described in paragraph 24 of the Concordat on Statistics.

3. Best practise relating to the efficient use of administrative data sources, including the design of a pipeline to sustain a statistical system reliant on administrative data, will be shared openly.

4. New and developing methods being considered for producing statistics in scope of this agreement should be shared openly and proactively between the parties of this agreement.

    • The signatories of this agreement will encourage the sharing of knowledge and resources between the parties; this may be through seminars or secondments.

5. The range of topics in scope of this agreement is likely to change over time. Common topics will continue to be used to provide the basis for common outputs, where necessary to meet common user needs.

6. In line with the Concordat on Statistics, coherent definitions and classifications should be used across the UK.

    • Where changes to definitions are considered, cross-working mechanisms will be used to agree the UK approach.

7. Where sources or methods for outputs in scope of this agreement differ, as a priority cross-working mechanisms will be used to maximise the harmonisation of outputs, with the objective of producing at a reasonable frequency:

    • Country-level estimates that can be aggregated to create UK-level estimates; and
    • For the topics of population, migration, income, labour market status and housing, subnational estimates that can be compared across countries. It is the long-term ambition of this agreement for the topics in scope of this subsection to increase over time, including priority areas such as ethnicity and general health.

Other areas for cooperation

8. The UK Statistics Authority’s ethical principles are to be followed as changes to methods and sources for statistics in the scope of this agreement are considered. The National Statistician’s Data Ethics Advisory Committee will be consulted as appropriate. Findings and recommendations of interest should be shared via cross-working mechanisms.

9. The parties will share experience of regulatory assessments and checks against the Code of Practice for outputs relevant to this agreement.

10. A common narrative will be agreed and updated at a reasonable frequency to provide users of UK statistics with information about cross-UK cooperation throughout this period of transformation in population and social statistics.


To promote UK harmonisation, every effort will be made to reach agreement through the cross-working mechanisms of the four nations. Any significant issues arising will be discussed and resolved at the Inter Administration Committee, in accordance with the Concordat on Statistics.

An annual report should be prepared for the Inter Administration Committee on the functioning of this agreement. Where notable changes occur in the coherence of population and social statistics across the UK, this report should include a discussion of these changes and the reasons behind them. Based on these reports the Inter Administration Committee will keep the terms of this agreement under review, and will expand on the agreement where necessary to support additional modes of cooperation facilitated by developing methods and best practise. Changes to the agreement will be subject to approval of all the signatories to the agreement.

Sir Ian Diamond, National Statistician
Paul Lowe, Registrar General for Scotland
Siobhan Carey, Registrar General for Northern Ireland
Stephanie Howarth, Chief Statistician for Wales
Alastair McAlpine, Chief Statistician for Scotland


Related links

Annual report on the functioning of the Statement of agreement: cooperation on future UK population and social statistics