📊 Add long-run UK migration data

[edomt]

Written by Claude Fable 5 — @edomt at the wheel.

Part of https://github.com/owid/owid-issues/issues/2469 (child of https://github.com/owid/owid-issues/issues/2464).

What this adds

A new dataset migration/2026-08-03/uk_migration with six indicators for the United Kingdom, 1853–2025: immigration, emigration, and net migration, each in people and as a share of the population.

The series is OWID-maintained (processing_level: major): it joins two sources at 2012.

• Up to 2011 — the Bank of England's research dataset A millennium of macroeconomic data (worksheet A19a), which splices four historical sources: ship passenger counts on extra-European routes (1853–1963), total migration counts (1964–1974), the International Passenger Survey (1975–1990), and Long-Term International Migration estimates (1991 onward). Converted from thousands to people; the Bank's share-of-population figures are kept as published (their denominator matches the UK's borders of the time, including all of Ireland before 1922).
• From 2012 — the ONS's administrative estimates of long-term international migration (year-ending-December values, which cover calendar years). These replaced the survey-based estimates as the official measure and are considerably higher — the survey undercounted flows in both directions — so the Bank's survey-based 2012–2016 values are discarded. Shares of population for this period are computed from OWID's population estimates.

Notes

• The indicator metadata spells out the five underlying sources period by period, the level shifts at each join (1964, 1991, 2012), the 1939–1946 gap, the pre-1922 boundary difference, and the 2001–2011 census revision of net migration.
• Sanity checks assert the join behaves as expected, that net = immigration − emigration everywhere except 2001–2011, and that values stay in plausible ranges.
• The Bank of England asks users to cite the workbook and the original sources of individual series; both are in the snapshot's citation_full.

🤖 Generated with Claude Code

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Login: ssh owid@staging-site-data-add-longrun-uk

chart-diff: ❌

• 0/2 reviewed charts
• Modified: 0/0
• New: 0/2
• Rejected: 0
• Data changes: 0
• Metadata changes: 0

data-diff: ❌ 1 new — full report

+ garden/migration/2026-08-03/uk_migration (new dataset: 2 table(s), 8 column(s))

Automatically updated datasets matching excess_mortality|covid|fluid|flunet|country_profile|garden/ihme_gbd/2019/gbd_risk are not included. Run locally with etl diff REMOTE data/ --include <dataset> --verbose.

Edited: 2026-08-10 12:09:42 UTC
Execution time: 24.62 seconds

[edomt]

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