The CBI told Alistair Darling yesterday that he had three weeks to appease it over his controversial reforms of capital gains tax (CGT) or face the “rage” of the business community.

The Chancellor faced his sternest critics at the employers’ group’s annual meeting in London yesterday. He told them: “I am listening to what you say,” but gave little sign that he would go back significantly on his surprise announcement last month that taper relief for capital gains would be abolished from April.

Richard Lambert, the Director-General of the CBI, which has been locked in talks with the Treasury over the proposals, said that Mr Darling had to deliver on his promise to publish final proposals on CGT in the next three weeks.

Asked what would happen if those revised plans did not go far enough, he said: “I think you would hear from us and other business groups, and loads and loads of businesses, a cry of rage.” It would leave “quite a substantial question mark” over the Government’s commitment to enterprise, Mr Lambert added.

Mr Darling had told the CBI that he still believed that it was “right and fair” for capital gains to be taxed on a flat basis. The proposed reforms had been controversial, he admitted, but were a response to the need to simplify the tax system.

However, he said: “We are working with the CBI and other business organisations to listen to what you have to say. I expect to publish final proposals in the next three weeks.”

The Chancellor also addressed the child benefit data fiasco that emerged last week. He said: “It is a huge problem, but one that has to be dealt with. That is what Government has to do in the face of problems like this. It is difficult, but we have to get on with it and sort it out.”

Mr Darling spoke after David Cameron had tried to wrest the mantle of the natural ally of business back from Labour, as he told delegates that he would fight the plans “every step of the way”. He refused to specify what the Tories would do if taper relief were abolished next year, arguing that there was still an opportunity to force the Chancellor to back down.