Any scholar of law will be familiar with the concept of certainty. The three certainties needed for a valid trust (intention, subject matter and objects or beneficiaries) are equally relevant to wills. A lack of clarity opens up disputes at a time least welcome to those involved, as in the case of Loring v Woodland Trust [2013] EWHC 4400.

Mrs Smith survived her husband who died in 1984. Both his death and her own last will and testament were prior to the change in the calculation of the nil-rate band. Mrs Smith herself died in 2011, almost four years after October 2007 since when a surviving spouse or civil partner can claim the relevant percentage of any unused nil-rate band.