Search any council's name plus “council tax” and the top results are rarely the council. They are aggregators — and a striking share of their figures are wrong. Having verified all 350 UK billing authorities for 2026/27, we can name the four failure modes.
1. Averages dressed as statutory figures
Wales publishes area-average Band D figures on GOV.WALES. Cardiff's average is £2,013 — but the statutory Band D on Cardiff's own page is £2,008.86. Aggregators copied the average as if it were the charge. Small error, but it is the difference between citing a statistic and citing the law.
2. Partial totals presented as the bill
Newcastle's Band D is widely quoted as £1,844.63. That is the city council's element alone — the actual bill including police and fire precepts is £2,540.66, nearly £700 more. Every figure on this site states exactly what it includes, and the precept structure is why partial figures are so easy to mistake for totals.
3. Stale pages and copy-paste chains
A viral claim that Coventry raised council tax 34.2% was false — a misread that propagated because aggregators copy each other rather than the source. Meanwhile councils' own pages sometimes lag: we found a stale GLA figure on Islington's page and last year's tables still live elsewhere. Dates matter, which is why every record carries a verified date and stale records degrade visibly rather than silently.
4. Nobody checks the arithmetic
Bands are fixed fractions of Band D (the ninths), so a published table that does not reconcile to the ratios contains a typo — that is how we caught a garbled Band H figure on Exeter's own page. Arithmetic checking is free; almost nobody does it.
What to do instead
Use figures that carry receipts. Every number on our national table links to the council's own page with a verification date, the rankings exclude anything unverified, and the full methodology — including our public corrections policy — is documented. If you reuse the data, it is free under CC BY 4.0 via downloads & licensing.