From: Mary Gregory, Executive Director, Population, Census and Social Statistics, Office for National Statistics
To: Ed Humpherson, Director General, Office for Statistics Regulation
Invitation to begin assessment for Census 2031 outputs (England and Wales)
Dear Ed,
I am writing as Executive Director of Population, Census and Social Statistics on behalf of the Office for National Statistics.
Many thanks for your letter of 11th May 2026 confirming the accreditation of 2021 Census in England and Wales outputs (excluding gender identity statistics) following the completion of the Phase 3 assessment.
In accordance with Section 12(1) of the Statistics and Registration Act 2007, I request an assessment of Census 2031 statistics for England and Wales. I am writing at this early stage of our preparations as we support the approach outlined in your letter, particularly the emphasis on a phased and flexible assessment process, enabling regulatory activity to be applied proportionately and focused on areas of greatest importance to users. This approach will also help us take on any lessons as we develop our plans and ensure we can provide the best value for users of our statistics.
As part of our planning, we are considering the recommendations arising from previous OSR assessment activity, as well as lessons from international activity.
ONS has also made substantial progress in response to OSR recommendations relating to Census 2021. We have focused on key areas:
Publication of a report on the Impact of the coronavirus (COVID-19) pandemic on England and Wales Census 2021 outputs, published in November 2025. This report sets out more detail on how key topics were affected and provides guidance on appropriate use of the data.
We are testing clearer and more consistent ways to highlight corrections and errors within statistical outputs including a new content lifecycle approach and clearer guidance to support users in interpreting revisions and understanding limitations.
As part of our content and website transformation, we are making improvements to accessibility and navigability. Census content will have a permanent, clearly structured presence, with improved tagging and search functionality driven by user research and analytics.
ONS is using insights from the Census Quality Survey to improve the 2031 questionnaire, while strengthening stakeholder engagement through forums, partnerships, and feedback.
We are currently undertaking a range of research activities to determine the design of the 2031 Census and analysing responses to the Census 2031 Topic Consultation (results due late 2026), We will be conducting a large-scale test of census design in a Census Test in March 2027 to help us determine the best approaches for Census 2031.
The Census 2031 Strategy for England and Wales sets out a strong commitment to the principles of the Code of Practice for Statistics, with trustworthiness, quality and value embedded throughout the programme. These are reflected in the core design and delivery principles, including:
ensuring outputs are high quality, trusted and meet evolving user needs
delivering secure, accurate and inclusive data collection across the whole population
producing coherent and comparable UK-wide statistics
delivering the programme efficiently, on time and with resilience
creating early benefits alongside a lasting data legacy for the future
As demonstrated in previous censuses, early engagement supports continuous improvement and ensures that outputs fully meet user needs and regulatory expectations across all phases of development, delivery and dissemination.
We would be grateful for the opportunity to discuss next steps, including timing, scope and the approach to assessment, and to agree how best to engage with OSR throughout the census programme lifecycle.
We also recognise the importance of your proposed approach to accreditation decisions being made ahead of publication, alongside transparent communication of their provisional nature where appropriate.
We look forward to working collaboratively with you as we seek to deliver Census 2031 providing users with outputs which meet the highest standards of trustworthiness, quality and value and continue to command the confidence of users and the public.
We are copying this letter to our Statistics Head of Profession (HoP) Office and our Census Outputs Statistical Design team who are ready to pick up the next steps with the OSR team.
Yours sincerely,
Mary Gregory
Executive Director for Population, Census and Social Statistics
Office for National Statistics