Delegates largely backed a US-led climate deal which included limiting temperature rises to less than 2C.

But the 193-nation summit ended with delegates taking "note" of the deal.

He (Ed Miliband) said some developing countries, such as China, did not want targets to be under international legally-binding obligations.

"They have doubts about whether we should, as a world, commit to a kind of bigger target, to say, for example - as the scientists say - we should cut our carbon emissions by 50% by 2050."

There was also "importantly, finance in the deal", he said.

The agreement outlined a goal of providing $100bn a year by 2020 to help poorer countries and also promised to deliver $30bn (£18.5bn) of aid for developing nations over the next three years.

Mr Miliband said there would be more transparency in about six weeks, when countries had agreed to put forward their targets.

He said he had "absolutely not given up hope, but it was important to move forward urgently" and a legal agreement "was still necessary".

Developed countries also needed to raise their ambition in terms of targets, he said.