The number of inheritance tax (IHT) investigations initiated by HMRC reached a six-year high during the 2025-26 tax year, with 4,940 formal enquiries opened. This represents an 18% increase compared to the previous year.
Alongside these formal investigations, nearly 5,000 further estates were referred to HMRC's compliance team for review before a formal investigation was launched. The data, obtained via a Freedom of Information request, indicates that the total amount of IHT collected reached a new annual high of £8.5bn in 2025-26.
HMRC is reportedly under pressure to address non-compliance and increase tax revenue. The frozen IHT threshold of £325,000, unchanged since 2009, combined with rising house prices, is drawing more households into the scope of IHT.
Common issues that can trigger an HMRC enquiry include property valuations, undeclared lifetime gifts, 'gifts with reservation' where the giver continues to benefit, and inconsistencies in asset reporting. Cross-border finances, particularly for long-term UK residents with worldwide assets, can also add complexity.