The Government’s proposed High Value Council Tax Surcharge (HVCTS), commonly referred to as the Mansion Tax, could have implications extending well beyond the additional annual cost of owning an expensive home.
With the Finance Bill 2026–27 now before Parliament, owners, buyers and sellers of residential properties worth £2 million or more should start considering its potential impact.
What has the Government decided?
From 1 April 2028, qualifying residential properties in England will be subject to an annual surcharge, in addition to ordinary Council Tax.
The proposed annual charges, based on April 2026 property values, are:
| Property value | Annual surcharge |
| £2m–£2.5m | £2,500 |
| £2.5m–£3.5m | £3,500 |
| £3.5m–£5m | £5,000 |
| £5m and above | £7,500 |
Charges will increase annually with CPI from 2029–30, with properties revalued every five years from 2033.
Impact on property values
One of the most significant implications is the potential effect on property prices.
The Office for Budget Responsibility (OBR) expects the annual surcharge to be reflected over time in the prices buyers are prepared to pay. It also anticipates some clustering of property values immediately below the relevant charging thresholds.
The OBR has modelled a 1.5% reduction in transaction volumes while valuation uncertainty persists.
These are forecasts rather than guaranteed outcomes, but the surcharge could become an important negotiating factor, particularly for properties close to the £2 million, £2.5 million, £3.5 million and £5 million thresholds.
Importantly, the agreed purchase price will not determine the surcharge band. Initial valuations will be based on April 2026 property values, meaning that negotiating a purchase below £2 million will not necessarily remove the property from the charge.
Ownership and conveyancing implications
Liability will generally fall on the legal owner rather than the occupier. This has important implications for properties held jointly, through companies or in trust.
Joint owners will be jointly and severally liable, while companies and trustees will be responsible for properties they own or hold.
For qualifying long leaseholds, liability will generally fall on the leaseholder where the original lease was granted for more than 21 years.
The legislation also provides for certain qualifying households to defer payment. However, deferred amounts may attract interest and be secured against the property.
Consequently, when a property is sold or transferred, accumulated liabilities and any registered security may need to be settled or discharged, much like an existing mortgage. These issues should be considered in pre-contract enquiries and completion arrangements.
Key dates
The principal milestones are:
- April 2026: Reference date for initial property valuations.
- Autumn 2027: Draft valuation bands expected.
- March 2028: First bills expected.
- 1 April 2028: Surcharge takes effect.
- April 2033: First scheduled revaluation.
What should property owners do now?
Although the surcharge will not take effect until April 2028, its potential impact on property values and transactions deserves attention now.
Owners of properties approaching the relevant thresholds should pay particular attention to the proposed valuations expected in autumn 2027 and be prepared to challenge inaccuracies.
For buyers and sellers, the new regime may also require closer consideration of valuation evidence, ownership structures, deferred liabilities and contractual arrangements.
Key considerations are:
- The Valuation Office will conduct valuations. It will use automated valuation models alongside professional valuer judgement. Home visits will only be used as a “last resort”.
- Homeowners will be able to see their draft bands in autumn 2027, ahead of the tax starting in April 2028, the Government has confirmed. There will be a process for challenging banding decisions.
- Especially for property close to £2m homeowners may consider appointing their own valuation surveyors to value their house, so they are ready to challenge the mansion tax valuation if they think it’s wrong.
The Mansion Tax should therefore be viewed not simply as an additional annual property tax, but as a factor that may influence property values, negotiations and the legal process of buying and selling high-value homes.
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