Is it true that a 160% council tax rise is coming?

Reports are rampant this week that Wandsworth’s new Conservative administration is “plotting Britain’s highest ever council tax rise”.

It is no coincidence that a by-election next week decides control of the council, and that Labour has been pushing this line hard to get Trinity voters to vote for it.

But the bigger question is: is it true? And if so, why would a Conservative council that has boasted for decades about the lowest council tax in the UK do something so unpopular?

This article will explain exactly what’s going on and give you a chance to play Wandsworth council finance chief…

The short answer

Yes, it is very likely that the Conservatives have been looking at something around 160 per cent as a top-end figure for next year. However, we should note that no published council document contains it.

Here is what matters more than the number itself. About 130 of the 160% is not something Wandsworth has much choice about. The Conservatives have published the figure on their website and noted that council tax “will need to increase by 130 per cent after the election” even if a much-touted council’s savings programme delivers everything it has promised. The same page puts the Labour government’s own working assumption at “more than 80 per cent”.

The difference between 130 and 160 is roughly what happens if those proposed savings do not arrive and if the shortfall falls entirely on council tax. Of the £45m a year the council is trying to save, only £14m has been identified, and so the extra 30% will be financial modelling for meeting current financial needs without applying potential savings or spending down reserves – which is what Wandsworth Labour was planning to do.

Both parties recognise – albeit very quietly – that council tax is going to jump significantly. What they are disagreeing about is whose fault it is.

The number that would settle it – what your bill will actually be in April 2027 – was due to be published in July. But then a by-election was called and it is now promised for September, after the election and after control of the council for the next four years has been decided.

Why a low-tax council would put your tax up

So why the huge increase in council tax? Because refusing to increase tax by that much will cost more than doing it. Here's how:

Central government has cut Wandsworth's grant, and it did so on the explicit assumption that the council would raise council tax to make the money back. The money has already gone. If the council charges less than the government assumed, the grant does not come back, the hole simply gets bigger.

That cut is part of the "Fair Funding Review", which is the government unwinding decades of a formula that gave Wandsworth far more central funding than councils in poorer areas. This is the uncomfortable part of Wandsworth's long-running "lowest council tax in the country" boast: it was never really about efficiency. Wandsworth's own finance officer told a committee in July 2025 that the borough was still living on "transitional protection" brought in twelve years earlier and meant to be temporary.

That protection was brought in after the last attempt to balance council tax across the country - but that time Wandsworth successfully argued that it should have a special dispensation so Wandsworth taxpayers didn't suffer a massive tax rise. This time around, the Labour government under Keir Starmer rejected that argument.

The Labour government did two other things that made it plain where it stood on the issue: it effectively imposed a flat-fee £150 increase, and it publicly and consciously lifted the normal restraints on councils where they are not allowed to increase local tax by more than 4.99% a year and said that for the next two years, Wandsworth (and five other council across England that are affected in the same way) will have no cap at all i.e. the council can raise council tax by as much as it wants without having to get permission from residents.

And if you are wondering how central government can effectively impose a flat fee and council tax rises, it's quite simple: money. It has provided its calculations to the six councils, told them it expects them to bring in the same amount per household as other parts of the country, and then said it will slow its financial cuts to the council so long as they increase council tax to match the cut itself. If Wandsworth doesn't do that, central government will cut the amount it provides faster.

Piggy banking

Or put more simply: imagine a parent who wants their child to learn how to start saving. They tell them that if they put £5 of the £20 a month allowance into a piggy bank they still get the £20. If they don't, they only get £10.

Roughly 55 per cent - about £130–135m of a £240m general fund revenue budget - of Wandsworth Council's income comes from central government. Council tax raises about £70–75m of the rest, with the balance from fees and charges (parking alone is over £40m a year).

So the answer to "why would they" is that the big decision has already been taken for Wandsworth Council, in Westminster, by a government of the opposite party. What is still a local choice is how much, how fast, and what gets cut instead.

A Band D household in most of the borough pays £1,020.35 this year. Of that, £525 is Wandsworth's own charge. The rest is the Mayor of London's precept and other levies, which the council collects but does not set.

That distinction matters more than anything else in this row, because every percentage being thrown around is calculated on one part or the other, and they give wildly different answers.

Take the government's own assumption first: 4.99 per cent plus a flat £150 added to the council's charge, in each of the two uncapped years. Wandsworth's share goes from £525 to £701 to £886. That is 69 per cent on the council's part of the bill, or about 40 per cent on the whole thing: roughly £1,420 a year landing on the doormat by 2028/29.

That is the floor, not the ceiling. It is what Westminster assumed Wandsworth would do, not what Wandsworth has decided.

Now the council's own arithmetic. Cabinet Paper 26-63, published in February by the outgoing Labour administration, forecasts the money the council must raise from council tax rising from £76.6m this year to £143.2m in 2027/28 and £178.4m in 2028/29 - up 87 per cent, then 133 per cent, "if other sources of revenue are not found". On a Band D bill that is around £1,760 a year.

Read those two together and the real gap appears. The council's own forecast of what it needs is higher than the government's assumption of what it will charge. That, not the distance between 34 per cent and 160 per cent, is where your money sits.

The scale of what has to be found is not in doubt either. Cllr Peter Graham, the cabinet member for finance, told cabinet on 30 July that the gap "next year is £96 million, rising to £145 million, rising to £168 million, rising to £184 million by 2030-31". Paper 26-63 states that one percentage point of council tax raises £0.77m. Closing £96m on tax alone would take about 125 percentage points.

Nobody will say the number until after you vote

When the Conservatives took the council in May they were one seat short of a majority. They govern with the support of Malcolm Grimston, the independent councillor for West Hill, under a confidence and supply agreement. Its first section deals with exactly this:

"The administration agrees to be honest at all times with residents about the council's funding position... In particular, the council tax rate required in April 2027 will be outlined in July 2026, as part of the Spending Review process. This will give residents time to prepare for changes to their bills."

The Spending Review went to cabinet on 30 July. It cancelled 253 council homes, scrapped holiday food vouchers for 10,000 children on free school meals, and ended the council's homelessness duty after a single refused offer of private rented housing. It contained no council tax figure.

Graham had said the week before that he could not set out financial plans because of pre-election restrictions imposed by the Trinity by-election. Those restrictions came into force the day after the meeting at which he said it.

If the Conservatives win Trinity they have a majority, and the agreement with Grimston - including that honesty clause - becomes something they are entitled to walk away from.

Kensington and Chelsea, facing the same settlement and the same removal of the cap, consulted its residents and got more than 400 responses. Wandsworth's residents will vote first and be told afterwards.

Labour's shameful role

The previous administration knew all of this was coming and did not prepare residents for it either.

In February, seven weeks before the election, the Labour administration under Cllr Simon Hogg announced a council tax freeze for the fourth year running, saying Wandsworth's high reserves and low debt were what allowed it. Appendix D of the same paper shows those reserves falling from £193.9m in April 2025 to £121.9m by April 2027: more than a third gone in two years.

The UK Statistics Authority wrote to Simon Hogg in March to tell him the freeze claim misled residents, because their bills had risen by 3.1 per cent. It was the first adverse finding the watchdog had ever directed at an English council leader.

Hogg, now leader of the opposition, said this week: "When Labour ran Wandsworth Council we had the lowest council tax in the country, the highest reserves of any neighbouring borough and no external debt."

That is a pure politician's argument: true, and highly misleading. Each claim stands up on its own. Together they describe one decision three times over, because the reserves were what paid for the low council tax. And "external" is doing the heavy lifting in "no external debt" — the council's own papers recorded £129m of internal borrowing in September 2024, and it agreed plans to borrow more than £1bn the following winter.

There is £121.9m of reserves left and a £96m gap next year, so spending the reserves works exactly once. The savings programme targets £45m a year, of which £14m has been identified; the council's own chief executive called the target "a broad, reasonable aspiration to get us going". Everything else has to come from council tax or from cutting something.

Whoever wins on 27 August inherits the same three levers and the same arithmetic as the interactive widget above.

So, will we see the largest ever council tax increases announced in September? Possibly, yes. Is there anything that any of the local parties can do about it? Not really, no. If you live in Trinity ward and you receive election leaflets this week claiming otherwise, you already know where they should go.