HMRC to Send Mansion Tax Inspectors to Homes Across the UK

Scope and Enforcement of Mansion Tax Inspections

The tax authority’s valuation agents will hold the power to demand entry to properties as part of the rollout for the levy, which was first introduced by former chancellor Rachel Reeves in the autumn budget. Officials will rely on third-party data and publicly available information to estimate initial property values before seeking physical access. According to the Valuation Office—part of HMRC responsible for maintaining council tax bands in England—internal inspections will be required where property attributes can only be confirmed inside or when a re-measurement is necessary.

Inspectors will assess property interiors, examining metrics such as the size and architectural style of homes, alongside counting bedrooms, bathrooms, and storeys. Homeowners who refuse entry to valuation agents face fines of up to £200 and commit a criminal offence, according to reporting from The Telegraph.

Implementation Timeline and Impacted Properties

The mansion tax is scheduled to take effect in April 2028 following a consultation period that concluded in July. Properties valued at over £2m will face an extra annual levy ranging between £2,500 and £7,500, contingent on the specific valuation of each home. Current projections from the fiscal watchdog indicate that the levy will hit 165,000 homeowners during its first operational year. That figure surpasses the 120,000 properties originally forecast under initial estimates.