HC Deb 13 June 1967 vol 748 c38W
41. Mr. Sheldon

asked the Chancellor of the Exchequer if he will undertake an investigation into the incentive and disincentive effects of changing the rates of taxation.

Mr. Callaghan

The effects of changes in the rates of taxation are always under investigation. I am of course willing to consider specific proposals for research in this field, if they offer a reasonable prospect of isolating the effects of taxation from other factors governing people's behaviour.