Measure What’s Important
Independent data on how Britain works. We take official UK datasets, normalise them, and publish the parts that are hard to get at — with the provenance chain attached, because a figure you cannot trace is a figure you cannot use.
UK statistical geography boundary changes
Every area in UK official statistics has a code. When a council is reorganised or a boundary review lands, those codes change: old ones terminate, new ones begin, and one old area may be split across several new ones. Anyone joining datasets across that moment hits it immediately — the join stops matching, and working out what replaced what means diffing two files.
ONS records all of it, in a 36 MB Access database inside a zip. We publish each reorganisation as one reviewable table: old code to new code, every successor named where an area was split, and the Statutory Instrument that made the change — or an explicit note where ONS recorded no instrument at all.
What is here now
- The 2024 westminster constituency changes
- The 2023 local authority district changes
- The 2019 local authority district changes
- The 2010 westminster constituency changes
- The 2009 westminster constituency changes
All 27 recorded reorganisations →
How to read anything here
Every page carries the source, the release we took it from, the date we fetched it, and the licence
— rendered from the record of that source rather than written into a template. Every data page
has a .json, .csv and .md twin at the same address, with no key
and no rate limit.
Nothing on this site is written by a language model. Pages are rendered from database rows, so a page cannot state a number the database cannot produce. Where a figure is missing we say it is missing; where a source has a gap we name the gap on the page it affects.
What is coming
A company insolvency series is loaded into the pipeline and not yet published. Anything else is gated on a licence we have actually read — see status for what we hold, what we are waiting on, and what we have decided not to use.