Efforts to secure a legally binding climate change deal failed last week because talks were "held to ransom" by a small number of countries, British prime minister Gordon Brown said today.

As the UK pointed the finger of blame at China for blocking progress at the UN-sponsored summit in Copenhagen, he called for a new international body to take charge of future negotiations.

Days of chaotic talks between more than 190 countries produced an accord that average world temperature rises should not exceed 2C but without commitments to emissions cuts to achieve it.

There was also agreement on a fund, to reach 100 billion US dollars by 2020, to help poorer countries deal with global warming, but no precise detail on where the money will come from.

Mr Brown, who spent four days in the Danish capital trying to secure a stronger deal, admitted that he feared the talks could collapse without even

those advances. In a webcast to be posted on the Number 10 site, he pledged to continue pressing for a binding deal and demanded action to ensure a minority of countries could not block future efforts.

"The talks in Copenhagen were not easy. and, as they reached conclusion, I did fear the process would collapse and we would have no deal at all," he said. "Yet, through strength of common purpose, we were able finally to break the deadlock and - in a breakthrough never seen on this scale before - secure agreement from the international community."

Calling on the world to "learn lessons" from last week's frantic scenes, he said: "Never again should we face the deadlock that threatened to pull down those talks; never again should we let a global deal to move towards a greener future be held to ransom by only a handful of countries.

"One of the frustrations for me was the lack of a global body with the sole responsibility for environmental stewardship. I believe that in 2010 we will need to look at reforming our international institutions to meet the common challenges we face as a global community."

Climate Change Secretary Ed Miliband earlier accused China of "hijacking" the Copenhagen summit and said Beijing had "vetoed" moves to give legal force to the accord and prevented agreement on 50 per cent global reductions in greenhouse emissions - 80 per cent in the most developed countries - by 2050.

Despite his frustrations, Mr Miliband insisted that Britain was right to sign the limited Copenhagen accord, which he said delivered "real outcomes" on temperature rises and finance. "We should take heart from the achievements and step up our efforts," he said.