Stephen Timms, the construction minister, has admitted that the government will not meet its climate change targets without cost to British industry.

Speaking at a fringe event of the Labour party conference, Timms told delegates there was no cost-free way to meet the target of a 60% reduction in carbon emissions by 2050, which was announced earlier this year.

Gordon Brown, the prime minister, said in his conference speech that he was looking at increasing the target beyond 60%.

Timms said: “There may be points at which the UK needs to take a lead on this, ahead of other countries, and we can’t kid ourselves into thinking there will be zero costs. We will need to make a decision between the government and society to find out how to meet this challenge.”

Meanwhile, Ken Livingstone confirmed at a fringe event that he would introduce a 20% renewable energy target for the capital’s boroughs.