asked the Secretary of State for Energy what is his best estimate of (a) the likely saving in petrol consumption in the first full year as a result of the increased petrol duty imposed in the Budget, and (b) the likely dissaving in petrol consumption in the first full year as a result of the proposed ending of the 50 m.p.h. and 60 m.p.h. energy-saving temporary speed limit.
First, the Budget increase in road fuel duty is expected to reduce motor spirit consumption by about 1 per cent. to 2 per cent. in 1977–78 below what it would otherwise have been, and by more in the longer term.Secondly, precise estimates of the effect on motor spirit consumption of ending the 50 m.p.h. and 60 m.p.h. speed limits cannot be made because of the many different factors involved.However, it is expected that any consequential increase in motor spirit consumption would be much less than 1 per cent.