Alistair Darling risks driving a wedge between different parts of the business community if the capital gains tax concessions announced on Thursday are focused on very small businesses.

A move to tax the first £750,000 of gains made by entrepreneurs or investors at a low rate – of 9 per cent or 10 per cent – would be likely to be well-received by some small-scale entrepreneurs and welcomed by the Federation of Small Businesses, which proposed such an “entrepreneur’s relief” in a submission to the chancellor in December.