Alistair Darling should address the “unintended consequences” of his capital gains tax reforms by offering significant concessions to business, Lord Jones, the trade and investment minister, said on Thursday.

The remarks by the former CBI director-general represent the first break in government ranks over the contentious CGT changes, which have triggered intense business opposition. Other ministers have voiced concern in private but insisted in public that they support the Pre-Budget Report decision to scrap taper relief and the 10 per cent CGT rate.