The number of estates in the UK subject to inheritance tax (IHT) will exceed 37,000 by 2027, according to analysis by Irwin Mitchell.

A report by the firm’s private client advisory team, based on findings from an HMRC Freedom of Information request, indicated that this could result in a total bill of almost £9bn.

The predictions in the Irwin Mitchell report are based on previously unseen statistics from the Government which cover 177,000 IHT estates across all 121 UK postcodes.

The forecasts have been adjusted to account for changes announced in Rachel Reeves’ Budget last year, which saw the current freeze to IHT thresholds extended until 2030 and changes to business and agricultural property relief from April 2026.

Irwin Mitchell’s report stated that the total amount of IHT in Greater London is predicted to grow by 54% between 2022 and 2027, increasing to £2.6bn a year, and the average IHT bill in Greater London is expected to be £275,000 by 2026/27, and even higher in Inner London (£340,000).

Leeds, Manchester, and Birmingham will also see double-digit increases in the percentage of estates liable for IHT.

National head of Irwin Mitchell’s private client advisory team, Andrea Jones, said: “The increase in IHT liabilities across the UK is a significant concern for many families.

“Our findings highlight the urgent need for individuals to seek professional advice to navigate these changes and plan effectively for the future.

“With the threshold freeze extended until 2030 and changes to business and agricultural property relief from April 2026, it’s more important than ever to understand the implications and take proactive steps to mitigate the impact on estates.”

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