Environmentalists say the UK government is talking impressively on climate change to its international audience, but down-grading energy policy at home.

World leaders open an historic summit in Paris aimed at ending decades of political gridlock and forging an elusive agreement to avert calamitous global warming.

The Government of France is going to host the 21st Conference of Parties (COP21) of the United Nations Convention on Climate Change (UNFCCC) in Paris from November 30 to December 11, where it is expected that a new climate change agreement will be signed.