The UK added about eight million people between 2001 and 2024. Almost everywhere grew.
Almost. Out of 361 local authorities, exactly 10 have fewer residents today than they did in 2001. Here they are.
| # | Local authority | Nation | 2001 | 2024 | Change |
|---|---|---|---|---|---|
| 1 | Kensington and Chelsea | England | 162,199 | 144,518 | -10.9% |
| 2 | Inverclyde | Scotland | 84,150 | 78,880 | -6.3% |
| 3 | West Dunbartonshire | Scotland | 93,320 | 89,120 | -4.5% |
| 4 | Argyll and Bute | Scotland | 91,300 | 87,690 | -4.0% |
| 5 | Ceredigion | Wales | 75,417 | 72,599 | -3.7% |
| 6 | Blaenau Gwent | Wales | 70,000 | 67,873 | -3.0% |
| 7 | Na h-Eileanan Siar | Scotland | 26,450 | 26,020 | -1.6% |
| 8 | North Ayrshire | Scotland | 135,820 | 134,010 | -1.3% |
| 9 | Dumfries and Galloway | Scotland | 147,780 | 145,860 | -1.3% |
| 10 | South Tyneside | England | 152,793 | 151,393 | -0.9% |
Figures are ONS mid-year population estimates (with NRS and NISRA for Scotland and Northern Ireland), retrieved via Nomis, 2001–2024, on modern authority boundaries throughout.
The rich borough at the top
The biggest faller in Britain is Kensington and Chelsea, which lost 17,681 residents, or 10.9% of its population. This is one of the wealthiest places in Europe.
The census tells the same story from a different angle: the borough's population fell 9.6% between 2011 and 2021, and the number of residents aged 25 to 34 dropped by 28.1%, around 9,800 people (ONS census area changes). Young adults left and were not replaced.
Why is harder to pin down, and worth being careful about. Affordability is the obvious candidate: a borough can price out the people who would otherwise fill it. Empty and lightly-used homes are often blamed too, though the numbers there are contested. Official figures put empty properties in the borough at under 2%, while Shelter has estimated that more than 10% are empty most of the time. Those measure different things, which is rather the point.
What the data does support is narrower than the headline: this is a decline in residents, not in prosperity or buildings. Worth remembering before anyone builds a narrative on the ranking alone.
The Scottish cluster
Six of the 10 are in Scotland: Inverclyde, West Dunbartonshire, Argyll and Bute, Na h-Eileanan Siar, North Ayrshire and Dumfries and Galloway sit on or near the list.
Inverclyde is the sharpest case outside London, down 6.3% since 2001. Greenock and Port Glasgow were shipbuilding towns, and the yards went. When the work that built a place stops, the young people leave first, which lowers the birth rate a decade later. That compounds quietly for a generation.
Argyll and Bute and the Western Isles have a different problem: they're rural, remote, and ageing. Deaths exceed births, and the people arriving tend to be retirees, which doesn't reverse the trend.
Wales, and one blunt number
Blaenau Gwent and Ceredigion are the Welsh entries. Blaenau Gwent covers Ebbw Vale and Tredegar, at the head of the valleys, where the steelworks closed in 2002. It has been losing people every year since.
Ceredigion is rural west Wales, and its fall is partly a student effect: Aberystwyth's university population swings the count.
What this doesn't tell you
A local authority is a big, blunt unit. Plenty of individual towns inside growing authorities are shrinking, and the council-level figure hides them completely. Our data can't see that, and neither can anyone else's without small-area census work.
The other caveat is boundaries. Several Scottish and English authorities were reorganised during this period, and where that happened the figures are for the modern area throughout, which is the right choice but not a perfect one.
The full series for every authority, year by year from 2001, is on the population trends pages. Each one has its own chart, and you can put any of their rates into the growth calculator to see where they lead.