Business anger over changes to capital gains tax intensified on Thursday after Alistair Darling delayed an announcement on concessions to his contentious reforms until the new year.

The delay will prolong the damaging uncertainty over changes to CGT, say business leaders and opposition politicans. It will mean thousands of small businesses and entrepreneurs will have to wait at least another three weeks before they know what rate of tax they will be charged on the sale of assets after April. Tax planners said the hiatus made it near-impossible to advise owners who are contemplating selling up.