Tax authority probes into households’ inheritance tax returns have surged to a six-year high, after a government-led crackdown on avoidance and non-compliance.

HMRC opened a total of 4,940 formal inheritance tax enquiries over the last financial year, according to new data obtained by chartered accountants Price Bailey, an 18 per cent increase on the previous 12 months.

The jump follows a widely touted clampdown on tax avoidance announced by Rachel Reeves in a bid to help balance the books and plug gaps in the public finances.

Formal enquiries are opened when there is a risk that an inheritance tax return may be incomplete or inaccurate. During the process, HMRC can demand documents, property valuations, and explanations from the family or accountant to ensure the correct amount of tax was paid. 

The fresh data follows inheritance tax receipts reaching a never-seen-before high of £8.5bn in the last financial year, as frozen thresholds make an ever larger number of estates liable for the unpopular levy.

Nikita Cooper, director at Price Bailey, said that HMRC is facing growing pressure to “clamp down on non-compliance and boost the tax take”, given the increasing number of estates “being caught in the tax net” each year. 

It comes as Reeves is targeting an extra £6.5bn in the Treasury’s tax intake a year by the end of Parliament through modernising HMRC and recruiting an extra 5,000 compliance caseworkers and 1,800 debt collection officers.

‘Significant administrative and emotional burden’ on grieving families 

Frozen inheritance tax thresholds, despite rising property prices and inflation, have led to a growing number of affected estates subject to the inheritance tax.

HMRC risk assessors also referred just under 5,000 tax returns for the levy to the compliance team, the highest number in five years. Despite this increase, the proportion of adjusted IHT returns continued to fall year-on-year.

Price Bailey revealed that only 40 per cent of compliance checks referred by risk assessors led to an amendment, down from 45 per cent the previous year. Both reveal stark decreases from the 83 per cent of returns amended in the 2021 financial year.

But Cooper warned despite the failure to lift the uptake, it still imposed a “significant administrative and emotional burden” on grieving families, “who have already complied with the rules”.

“This is unfair on the taxpayers who are coping with bereavement and are doing the right thing by making full and accurate disclosures,” Cooper said.

As new changes to the inheritance tax regime come into effect next year, including pensions falling into the scope, Price Bailey forecast enquiries to further rise.