HM Revenue and Customs will deploy valuation agents to conduct in-person property inspections to determine which homes fall under the new High Value Council Tax Surcharge, according to reports.
The Sunday Telegraph has revealed that HMRC inspectors will visit properties to assess whether they meet the £2 million threshold for the surcharge, commonly referred to as the mansion tax, which takes effect in April 2028. Homeowners who refuse access to inspectors will face criminal penalties, with fines of up to £200 for non-compliance.
Scope of inspections
Valuation agents will conduct detailed assessments of property interiors, including the number of rooms, storeys, bedrooms and bathrooms. The government confirmed to the Telegraph that multiple valuation methods will be employed to determine property values.
According to Zoopla data, approximately 183,000 homes in England are currently valued at or above the £2 million threshold. A further 75,000 properties sit just below this level, potentially bringing the total number of affected properties to 258,000 if values appreciate before the tax’s implementation.
Tax structure and revenue implications
The annual charge will be set at £2,500 for properties valued at £2 million or more, with higher rates applying to homes valued above £2.5 million, £3.5 million and £5 million. The tiered structure aims to generate additional revenue from high-value residential property.
The policy has drawn criticism from the Conservative Party, which described the inspection regime as “a sinister assault on civil liberties”. In an editorial, the Telegraph argued that the tax “effectively turns families into tenants in their own homes, at risk of losing their property if they are no longer willing or able to pay the state for the pleasure of owning it”.
The implementation of the High Value Council Tax Surcharge represents a significant development in UK property taxation, particularly affecting owners of high-value properties whose maintenance decisions could influence their tax liability. The inspection programme will require substantial administrative resources from HMRC, though the government has not disclosed the expected compliance costs or the number of valuation agents to be deployed.
Market implications
Property professionals will need to advise clients on the valuation process and potential tax liabilities ahead of the 2028 implementation date. The policy may also influence property values near the threshold, as some owners may seek to demonstrate valuations below £2 million to avoid the charge. With agents already managing complex compliance requirements, the new inspection regime adds another regulatory dimension to property transactions in the upper end of the market.
The government has not yet published detailed guidance on the inspection process, appeals procedures or the frequency of revaluations, leaving questions about how the scheme will operate in practice when it launches in 2028.
