asked the Chancellor of the Exchequer what is his estimate of the loss to the revenue of providing full tax relief on national insurance class 1 contributions on the one hand and Class 2 and 4 contributions, taken together, on the other in 1975–76.

Information on which to base a precise calculation is not available but it is estimated that the full-year cost for 1975–76 would be of the order of £750 million for tax relief on Class 1 contributions and £80 million for Class 2 and 4 contributions taken together.