The "mansion tax" consultation closes tomorrow — and buyers are already negotiating offers to dodge the £2m threshold

Bit of a different one from the usual FTB/gazumping stuff on here, but I think it's genuinely interesting even if you're nowhere near this price bracket, because it shows how a tax that hasn't even been finalised yet is already reshaping how people negotiate.

Quick recap for anyone who missed it: back in November 2025's Budget, Rachel Reeves announced a new "High Value Council Tax Surcharge", everyone's just calling it the mansion tax, on residential properties in England valued at £2 million or more. It's currently out for public consultation, and that consultation closes tomorrow, 14 July 2026.

How it's shaping up so far:

Threshold: £2m+. Roughly 165,000 households would be affected initially, and it's heavily concentrated, around half of all £2m+ homes are in London, and London plus the rest of the South East account for about 85% of them between them.

Cost: an annual surcharge somewhere between £2,500 and £7,500 depending on value, stacked on top of your normal council tax bill.

Timeline: valuations are being done this year (2026), but nobody actually starts paying until April 2028. Money goes straight to the Treasury, not your local council.

The bit I find genuinely fascinating: data from February 2026 showed that 83% of offers on homes priced within 10% of the £2m mark came in below £2m. That's buyers and sellers already quietly negotiating around a tax threshold before it's even law, pricing a home at £2.05m and watching it get talked down to £1.98m, that kind of thing. If you're house hunting anywhere near that bracket, this is worth knowing about now, not after you've made an offer.

Also worth flagging if you think "not my problem, I'm not buying a £2m house": there's been talk of eventually lowering the threshold to £1.5m, which the estimates suggest would pull in another ~150,000 households. Worth keeping half an eye on if you're buying somewhere that's crept up in value over the last few years.

Criticisms doing the rounds: valuations are reportedly going to be done via desktop methods (comparable sales data + aerial imagery) rather than physical inspection, which people expect will trigger a wave of appeals for anything remotely unusual (listed buildings, big gardens, converted properties etc). There's also a fairness argument being made for "asset-rich, cash-poor" owners, think retirees who bought decades ago in an area that's since gone up in value and are now sitting on a tax bill with no extra income to match. And social housing is exempt, which raised some eyebrows given more than 110 social homes have actually sold for £2m+ since 2021.

Because the consultation closes tomorrow, this is basically the last call if anyone wanted their view on record before whatever comes out of it gets finalised.

Curious what people here think: fair way to raise revenue from genuinely expensive property, or just a proxy wealth tax dressed up as council tax reform? And if you're currently buying anywhere near the £2m line, are you already factoring this into how you're negotiating?

Sources: HomeOwners Alliance — how the mansion tax will work | Willow Private Finance — consultation deadline | HomeOwners Alliance — valuations guide