This £100 million year-on-year increase, documented by HMRC, stems from a combination of appreciating asset values and long-term stagnation in tax thresholds.

Central to this growth is the “fiscal drag” caused by the main nil-rate band remaining frozen at £325,000 since 2009. By failing to adjust this limit in line with inflation, the Treasury has ensured that an ever-increasing number of estates are ensnared by the 40% levy.

While a secondary £175,000 allowance exists for those inheriting a primary residence, the overarching freeze has transformed what was once a tax on the wealthy into a consistent and expanding revenue stream for the Exchequer.