The UK Budget earlier this week confirmed that the Inheritance Tax (IHT) threshold will not be changed until 2026 at the earliest – meaning that it will have been kept at the same rate for 17 years.

London-based private wealth law firm Boodle Hatfield has warned that increasing asset values, coupled with inflation, will mean thousands more estates will likely be liable to pay the tax over the coming years.

The threshold for IHT has been fixed at £325,000 since April 2009. The rise in value of as...