The British government is due to announce its draft climate change bill today, aimed at cutting CO2 emissions by 60% by the year 2050. The law gives the UK the world’s first legal framework for transition to a low-carbon economy.

Under the bill, carbon “budgets” will be set every five years following independent advice. The Environment Secretary David Miliband has rejected opposition calls for annual targets on reducing emissions.

“Changing your policy on the basis of one year’s weather isn’t a sensible way of doing things,” said Miliband. The government will also have to report annually to Parliament on its progress in controlling emissions.

Christian Aid’s senior climate policy officer, Andrew Pendleton, said: “Mr Miliband is to be congratulated for publishing the bill and he is right to be proud of it – he and the government are an example to the rest of the G8. “But if the final legislation is not significantly stronger, the process would represent a massive lost opportunity. It is the first step on a long journey rather than the destination itself.”