Steep increase in families caught by inheritance tax The number of estates affected by the tax each year is due to double from 21,000 last year to 42,000 in 2016/17 - far beyond the previous peak of 34,000 under Labour in 2006/07, accountants predict. The upturn in house prices surprised Britain's economic forecasters. In March, the Office for Budget Responsibility said house prices would rise by 1.6pc in 2014, yet Savills, the estate agent, predicts they will go up nationally by 6.5pc. Mike Warburton, a director at Grant Thornton, the accountancy firm, used the Savills housing forecasts to calculate the cost of the freeze. "It was always likely that freezing the threshold would bring more families into inheritance tax, but this has been brought into sharper focus by the recent revival in the housing market," he told The Sunday Times. The Treasury said: "Over 96pc of all estates do not have to pay inheritance tax. Since 2009, the value of core estate assets such as domestic property has fluctuated significantly. Despite this, the number of estates paying tax has remained at less than 4pc for over four years.