NRRW: employment and follow-up information
Published 4 June 2026
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This publication is available at https://www.gov.uk/government/publications/nrrw-employment-and-follow-up-information/nrrw-employment-and-follow-up-information
Employers provide records of employment episodes, occupational exposure to ionising radiation and some personal identifying data including name, date of birth, sex and sometimes National Insurance number.
In the early days of the UK nuclear industry most radiation workers only had a single employment, but in recent years more workers are having multiple employments as radiation workers, either directly with the employers who manage the sites or indirectly via contracting companies. It is very important that all the occupational radiation doses received by a worker are recorded on the National Registry for Radiation Workers (NRRW), so as to avoid bias in the estimates of risk from the study caused by missing doses.
Therefore, once a worker is registered on the NRRW, if they have later employments at the same site via a contracting company or move to another site managed by an employer that is also is part of the NRRW and work there either as a direct employee or via a contractor, then we will endeavour to continue to collect the above information during such employments, unless they ask to withdraw from the study.
For workers in England and Wales their National Health Number, obtained from the NHS spine IT system, is used to uniquely identify them for collecting follow-up information (cancer incidences and mortality data). In Scotland, the individual identifier is called the Community Health Index number but serves the same purpose.
The route by which follow-up information is obtained about participants living in England and Wales has changed several times over the life of the study.
Currently, the UKHSA Office for Data Release (ODR), which manages secondary-use access for UKHSA studies to Office for National Statistics (ONS) mortality data, provides mortality data for England and Wales, while cancer incidence data for England and Wales is provided by NHS England.
The National Records for Scotland provides mortality and cancer incidence data for workers living in Scotland. This route has remained the same over the life of the study.
Welsh cancer incidence data is collected directly from the Welsh cancer registry.