asked the Chancellor of the Exchequer what is the estimate for (a) 1979–80, and (b) 1980–81 of mortgage income tax relief on the assumption of unchanged mortgage interest rates.

The estimated cost of mortgage interest relief for 1979–80 is about £1,450 million. The cost for 1980–81 will depend on the rates of tax and personal allowances for that year as well as the level of incomes and is not at present available.