If the estate falls below the threshold which is currently set then IHT is not payable.
There are ways to mitigate IHT. In fact, it is sometimes called: “an optional tax”. Indeed, if the estate is significant, then forward planning can dramatically reduce IHT or even eliminate it.
IHT is also payable on gifts made within seven years of death. This is to avoid a person giving away their property, for example, when they know they will soon die, and thus avoiding Inheritance Tax.