Estimating the constituency distribution of a mansion tax

The Times reports that Chancellor Rachel Reeves plans to raise up to £450 million from a levy on homes worth over £2 million, affecting over 100,000 properties. Earlier speculation suggested a £1.5 million threshold, which would have affected 300,000 homes.

To illustrate where a mansion tax would have the greatest impact, we mapped 2024 Land Registry sales above these thresholds by parliamentary constituency. Sales data serves as a proxy for the stock of high-value homes; turnover rates vary by area, so these figures show the relative geographic concentration rather than the total number of homes that would be affected.

Raising the threshold from £1.5 million to £2 million nearly halves the number of affected properties:

Threshold	Sales	Share of all sales
£1.5 million	14,820	1.7%
£2 million	8,213	0.9%

Three central London constituencies—Cities of London and Westminster, Kensington and Bayswater, and Chelsea and Fulham—account for 16% of affected properties at the £1.5m threshold and 21% at the £2m threshold. The median constituency saw 10 sales above £1.5m or 6 above £2m.

London constituencies account for 45-46% of all affected properties. Outside London, the constituencies with the most high-value sales are Runnymede and Weybridge (183), Queen's Park and Maida Vale (166), Esher and Walton (163), Windsor (134), and Chesham and Amersham (127).

Use the toggle to switch between £1.5m and £2m thresholds.

The top 10 constituencies account for 30% of sales above £1.5m and 36% above £2m. All are in London or the commuter belt.

Top 10 constituencies by share of nationwide high-value sales

Constituency	£1.5m	£2m
Cities of London and Westminster	6.7%	9.5%
Kensington and Bayswater	5.5%	7.0%
Chelsea and Fulham	4.2%	4.6%
Hampstead and Highgate	2.7%	3.0%
Battersea	2.2%	1.7%
Richmond Park	2.0%	1.9%
Islington South and Finsbury	1.7%	1.7%
Hammersmith and Chiswick	1.7%	1.6%
Holborn and St Pancras	1.5%	1.7%
Finchley and Golders Green	1.3%	1.4%

We identified 2024 property sales exceeding £1.5 million and £2 million from Land Registry Price Paid Data, which includes postcodes for each transaction. We mapped postcodes to parliamentary constituencies using MySociety's 2025 constituency lookup, then uprated prices to 2026-27 values using the OBR house price index forecast (+3.56%) from the October 2024 Economic and Fiscal Outlook.

Limitations: We use sales as a proxy for housing stock, apply the national house price index uniformly (regional growth may vary), and properties near thresholds may be revalued.

Download the constituency dataset (CSV) | View code on GitHub