Energy Secretary Ed Miliband pledged to "throw everything" at securing a global climate change deal as leading nations gather in London for talks. Representatives of 17 countries are in the UK for the Major Economies Forum with just 50 days to go until a crunch UN-sponsored summit in Copenhagen. Mr Miliband said the talks provided a vital forum to narrow the gaps between nations and avoid a catastrophic failure to cement a fresh agreement in December. "Today is the beginning of the end game," he said. For a deal to succeed it would need mid-term targets for cuts from developed countries, for example by 2020, as part of efforts to more than halve global emissions by mid-century, as well as action from developing countries. Mr Miliband also said it was crucial that world leaders were involved in drawing up a new global deal by the end of the year, with the role of heads of state including US President Barack Obama critical. Prime Minister Gordon Brown has pledged to go to Copenhagen to help secure a deal and has urged other world leaders to follow suit. Major emitters including China and India have expressed concerns that the old treaty, the Kyoto protocol, with its legally binding commitments from developed countries, will be thrown aside in favour of a new deal. But officials in the UK believe the negotiations must build on Kyoto and ensure the US - which never ratified the protocol - is brought into a new agreement.