Illegal immigration to the UK, measured.

The most-asked question, answered honestly: nobody publishes that number — including the Home Office, which says so in writing — and here is what the published figures actually count.

Each measure compared with itself at the two ends of its own series, with its peak — and a plain statement of what two dated points cannot show.

17,480 small-boat arrivals so far this year, tracked weekly against prior years.

40,168 awaiting an initial decision — down from a peak of 175,457 — with grant rates including small-boat claims by nationality.

Asylum accommodation contracts re-estimated from £4.5bn to £15.3bn over ten years — every figure a verified NAO citation.

10,134 foreign nationals in prison; 21,294 FNOs subject to deportation action living in the community.

English language, extremism referrals, inquiry findings and public opinion — official sources, quoted exactly.

Asylum accommodation in every UK local authority, from dispersal to contingency hotels.

16,021 people in contingency hotels — the population over time, every local authority with places, and what the NAO says they cost.

The tribunal backlog that the initial-decision backlog feeds — and the cohort analysis showing final grant rates after appeal.

Arrivals, claims and grant rates by nationality — with the prison figures kept deliberately separate.

Every headline number on this site in one list, each with its period and a link to the official source.

Every cleaned dataset behind this site as CSV and JSON, with provenance headers. Check our workings.