Corrections
Where a figure published here has been wrong, this is the record of it
A site that asks to be cited has to be accountable for its own mistakes, not
only for the publishers' revisions. This page records errors in figures
this site published: what was wrong, what it should have been,
and what changed so the same class of error cannot recur.
Figures restated by the Home Office or the Ministry of Justice are a different
thing and are recorded separately in the revisions ledger (5 restatements).
Foreign national offender returns, all years
Found 27 August 2026.
| What went wrong | The returns table's unique constraint used Postgres' default NULLS DISTINCT semantics. FNO rows carry NULL age_band and sex, so the loader's ON CONFLICT target never matched and each refresh inserted duplicate rows instead of updating: every FNO year doubled on reload (2025 showed 11,415 against a true 5,732). |
| What was changed | Constraint recreated as UNIQUE NULLS NOT DISTINCT, and the validation oracle extended to reconcile FNO returns against the Home Office's own Ret_02a table so the same class of error cannot pass unnoticed again. |
| Scope | Caught before publication. No incorrect figure was ever served: it is logged here because a near miss in the figures is worth recording, not because anything published was wrong. |
| Fixed in | f3cd572 |
Prison population for Congo (COG), 2025 Q4
Found 19 August 2026. Published as 28; corrected to 41.
| What went wrong | Two distinct MoJ demonyms both mapped to the ISO code COG. The loader's upsert key was (year, quarter, ISO), so the second row overwrote the first instead of being added to it, silently dropping people from the Congo figure. |
| What was changed | The parser now aggregates by ISO before loading, so colliding demonyms sum rather than overwrite. |
| Scope | One country, one quarter. Site totals were unaffected because the national total is taken from the MoJ summary table, not from summing countries. |
| Fixed in | a139364 |
How corrections are handled
- Corrections vs revisions. A correction is our error. A revision is the publisher restating its own figure, which happens routinely because recent periods are provisional. The two are kept apart deliberately: presenting our mistake as an official revision would be false.
- Found something wrong? Email contact@deported.co.uk with the page and the figure. Every number on the site names its source table, so a disagreement can usually be settled against the publisher directly.
- Near misses are logged too. Where an error was caught before anything was published, it is recorded and labelled as such rather than quietly dropped.