Research by estate agency Hamptons suggests that over 3,300 second homes could be directly affected. The surcharge will target properties valued at more than £2 million, while the government estimates around 100,000 of Britain’s most expensive homes will be hit, with the average household paying an additional £4,500 annually. Hamptons calculates the number of homes over the £2 million threshold could exceed 125,000.
The tax, expected to generate between £400 million and £450 million, will require the revaluation of 2.4 million properties in the highest council tax bands; F, G, and H placing the most expensive homes under the new levy.
Over 200 councils in England have already introduced a second-home surcharge this year, allowing them to double council tax bills for secondary properties. Hamptons’ analysis for Times Money identified nearly 4,960 second homes likely valued above £2 million, with around 3,340 in areas liable for both the 100 per cent council tax premium and the mansion tax.
The average Band H council tax bill in 2025-26 was £4,600, meaning second-home owners could face more than £9,200 without the surcharge. With the mansion tax added, annual bills could reach £13,700 or more. Rutland, in the East Midlands, tops the charts with Band H homes billed at £5,342, potentially exceeding £15,000 for second-home owners in properties above £2 million.
Even in London’s Wandsworth, where Band H tax is £1,980, the lowest in England second-home surcharges could push bills beyond £8,000. Band G homes across England average £3,835, with surcharges potentially exceeding £12,200 for 835 properties over £2 million.
David Fell of Hamptons said: “While there aren’t many second homes worth over £2 million, they have been hit hard by double council tax bills and the mansion tax on top. In high-value areas, property tax bills could reach £15,000 a year.”
The current version of the mansion tax, expected by 2028, has been scaled back from initial proposals targeting homes above £1.5 million, which would have affected 300,000 homeowners. The government plans to allow deferrals until a property is sold or the owner dies, avoiding forced sales to pay the tax.
Experts warn the £2 million threshold may distort the property market, with sellers adjusting asking prices to avoid the surcharge. Lucian Cook of Savills said: “Fixed-price thresholds will create market distortions. Buyers will hesitate to pay above them, and sellers are likely to lower prices accordingly.”
Hamptons found that roughly 28 per cent of affected homes would be valued between £2 million and £2.1 million, based on advertised rather than sale values.
Property professionals also anticipate disputes between councils and homeowners over valuations. Tom Bill from Knight Frank noted: “Prime streets often have wide value variation, leaving valuations especially cursory ones open to challenge.” Around 30 per cent of English homes haven’t sold since 1995, complicating accurate valuations further.
