HMRC inspectors will be able to visit homes to establish whether they are liable for the new mansion tax, according to a report in The Telegraph.

The High Value Council Tax Surcharge, commonly referred to as the mansion tax, is due to come into effect in April 2028 and will impose an annual charge of between £2,500 and £7,500 on properties valued above £2m.

HMRC’s Valuation Office will initially use publicly available information and third-party data to estimate property values.

However, according to the report, valuation agents will assess properties where information needed to determine whether they are worth more than £2m cannot be confirmed using existing records or other data.

Inspections could be required where property characteristics “can only be confirmed internally or a re-measurement is required”, according to the report.

Inspectors could assess features including the size and architectural style of a property and the number of bedrooms, bathrooms and storeys.

The Telegraph also reported that valuation agents will be able to demand entry to properties where an inspection is required.

Owners who refuse to cooperate with an inspection risk a £200 penalty and could be prosecuted, the newspaper said.

The High Value Council Tax Surcharge was announced by former chancellor Rachel Reeves in last year’s autumn Budget, with a consultation on its implementation ending in July.