§ Sir B. Rhys Williamsasked the Chancellor of the Exchequer what study he has made of evidence available from field surveys of the effects of marginal tax rates upon incentives; and what opinion he has formed as to the marginal rates at which disincentive effects become significant.
§ Mr. Taverne:I am not aware of any evidence about the effects of taxation on incentives which would lead to a firm conclusion on the question. I refer the hon. Gentleman to the letter of 29th April. 1969 from my right hon. Friend the Chief Secretary to the hon. Member for Ashton-under-Lyne (Mr. Sheldon), a copy of which was placed in the Library.