Prime minister Gordon Brown strongly has strongly defended his new 18% CGT rate after Tory leader David Cameron demanded chancellor Alistair Darling 'resolve the uncertainty' over the future structure of the tax.

Brown was challenged over the controversy surrounding the scrapping of CGT taper relief at his first prime minister's press conference following the pre-Budget report which scrapped taper relief.

He said the new 18% rate was half the 40% rate when Labour came to power in 1997 and said it compares with 22.5% in Germany, 25% in the USA, 33% in France and 40% in Japan.

He said: 'I think this debate about CGT has got to be seen in its proper context.'

Cameron told the CBI he wanted Darling to make clear 'what the CGT will look like in five months' time', adding, 'the best thing he could do is stand up, admit he's made a mistake and abandon his nil-considered plans.'

He urged against applying sticking plaster to proposals he believed had angered entrepreneurs and the business community.

He said the question was whether the proposed simplification would make the UK a better place to be an entrepreneur and create wealth and jobs.