Like many pieces of tax legislation, the ‘additional threshold’ (AT) for Inheritance Tax (IHT) – which, in simple terms, limits the potential IHT charge on high-value residential properties – is a lot more complicated than it looks at first sight.

However, HM Revenue and Customs have helpfully created a calculator which, when combined with other information extracted from the IHT forms, will enable the administrators of an estate to calculate how much AT is available.

Where AT is able to be claimed, it tapers for estates above £2 million. The relief is available where the death takes place on or after 6 April 2017.