Celebrate Grandparents' Day by planning to beat the taxman IT IS officially national Grandparents' Day, making it an ideal time to think about your own finances and how you can help your family plan for their own future - and a burning issue in all of this is inheritance tax (IHT). In the UK, IHT is levied at 40 per cent on assets over £285,000 and in the wake of spiralling house prices, an increasing number of families are over this threshold. .