How do the UK police and Home Office define and record 'migrant' in crime statistics?
Executive summary
There is no single, consistent UK official definition of "migrant" used in crime statistics: academics and government bodies use different concepts (for example "foreign‑born" or "non‑citizen"), police recording focuses on nationality or custody data rather than a migration status label, and the Home Office holds immigration records separate from police crime data — producing partial, sometimes incompatible picture across agencies [1] [2] [3].
1. What people mean when they say "migrant" — multiple definitions coexist
In research and briefings the working definition of "migrant" often defaults to "born outside the UK" (foreign‑born), but other definitions in official and policy debates include "non‑citizen", "recent arrival", or specific legal categories such as asylum seeker, refugee or irregular entrant; the Migration Observatory notes these definitional choices change results and policy implications [1] [4].
2. What the police actually record about nationality and immigration status
Police recorded crime datasets do not routinely classify offenders by a single migration label; what is most commonly captured is nationality or details taken at custody, but forces vary in completeness and practice and the ONS emphasises its publications concern how crime is experienced or recorded by police rather than offender immigration status — the ONS told requesters it does not hold a simple breakdown of crimes by “migrant” and “illegal migrant” the way some ask for [2] [3] [5].
3. The Home Office holds immigration status data but it is not seamlessly linked to crime records
Immigration status and outcomes are managed by the Home Office, which maintains administrative records on visas, asylum claims and removals, but those datasets sit separately from police crime statistics and the ONS points requesters towards the Home Office for immigration figures; in practice producing robust cross‑tabulations of crime by immigration status requires data linkage that is not routinely published [2] [3].
4. Who compiles and publishes the numbers — fragmentation across agencies
The ONS produces crime statistics using Police Recorded Crime and the Crime Survey for England and Wales, the Ministry of Justice holds offender and sentencing data, the Crown Prosecution Service publishes charging figures, and the Home Office supplies immigration statistics — none of these bodies singularly publishes a comprehensive, validated table of crimes by a consistent "migrant" category, and the ONS explicitly directs users to MoJ or Home Office for offender nationality/immigration details [2] [3].
5. Key limitations that shape the data and common misreadings
Three structural problems recur in the evidence: first, different definitions (foreign‑born vs non‑citizen vs asylum seeker) produce different rates and comparisons [1]; second, demographic confounders such as age and sex matter — non‑citizen populations skew younger, inflating crude arrest or conviction shares unless adjusted [4]; third, administrative gaps and undercounts exist for short‑term migrants, unauthorised migrants, and people in communal establishments, meaning both population denominators and offence attributions can be biased [4] [5].
6. What this means for interpreting claims about "migrant crime"
Because police data are inconsistent on migration markers, Home Office immigration records are separate, and researchers often adopt different definitions, claims that migrants commit a specific share of crime are frequently based on partial slices of data or unadjusted comparisons; rigorous analysis requires clear definition, age‑sex adjustment and careful linkage across MoJ/ONS/Home Office sources — none of which is standardised in routinely published crime tables [3] [4] [2].