Al Gore has launched a scathing attack on David Cameron for ditching a series of environmental measures since winning reelection in May.
In a highly unusual intervention in British domestic politics, the former US vice president accused the prime minister of u-turning on a series of personal promises he had made five years ago and came close to accusing Cameron of betrayal.
Speaking in London on Tuesday morning, the Democrat said he had heard "whispers" from No.10 Downing Street that Cameron is being blocked from pursuing green policies by others inside the government.
"I have been partisan in my country. I have never dared to express a partisan view in this country, I have refrained, as I should, I am not a citizen of your country. But too much is at stake," he said.
"Since the election was held, this country’s commitment to zero carbon homes has been cancelled. This country’s commitment to carbon build has been cancelled, the green deal has bee cancelled. The climate change levy exemption for zero carbon energy has been cancelled. Solar support via the renewables obligation has been cancelled. Onshore wind support via the renewable obligation has been cancelled," he said.
Gore, who became a vocal advocate in favour of tackling climate change since leaving the White House in 2000, also attacked Cameron's government for expanding fracking and its plans to privatise the Green Investment Bank.
"I was personally invited by your prime minister before he was prime minister to come and meet all of the ministers of parliament in his party. And I heard pledges and commitments that really inspired me. And I was grateful and encouraged and hopeful. And I have heard some speeches since then that have reawakened the kindling of that same hope. I know there will be a speech next week."
Hitting the podium in frustration, Gore added: "Words. Words. What about actions? The actions that have been taken here in the last few months are puzzling to me."
David Cameron 'hugging a husky' in 2006 when leader of the Opposition
Asked if he felt "betrayed" by Cameron, Gore said: "Do I feel betrayed? I will not use that word. I purposefully use the word 'puzzled' and I don’t intend it to be swimming in sarcasm.
"I would be tempted to use that word. But I don’t want to personalize this. I have great respect for the prime minister. I like him as a person.
"I see it in my own country where people who are well meaning can be persuaded to do things that are really not in the best interests of their county."
As leader of the Opposition, Cameron famously travelled to Norway to 'hug a husky' and demonstrate his environmental credentials. In the run-up to the 2010 election he said he wanted to lead the "greenest government ever".
However in 2013, as Cameron faced an uphill battle to win reelection, it was reported he had told aides to get rid of the "green crap" and focus on core economic messages.
Gore said today: "I am a student of politics. I hear whispers from No.10 that remind me of palace intrigue of some-sort. Who is the leader? Who makes these decisions? I am comforted by mutual friends of your prime minister that he personally still believes very strongly in this and that he somehow does not really have the ability to take on control of these decisions. I do not believe that."
The former American vice president was also asked for his opinion on George Osborne. Gore indicated Cameron should be strong enough to overrule his chancellor if it was him that was engineering environmental policy u-turns.
"I don’t really know him. And so I don’t think it would be proper for me to comment," he said of Osborne. "But I will return to a point I stressed earlier, he’s not your prime minister."
Ahead of a major climate change conference in Paris, Gore said the UK needed "revive the leadership that it friends around the world has so long admired".
He said: "There are very few of those great moral questions that we have encountered in the past, from abolition [of slavery] to womens' suffrage, to civil rights and gay and lesbian rights, there are very few of these questions where the UK has not been heard loudly and clearly. This is such a question. Because it involves the survival of humankind."
Gore also warned the British government to pay attention to Mark Carney, the governor of the Bank of England, who has warned about over investment in fossil fuels.
"When the leader your of central bank raises questions about the viability of the financial system if they are not steps taken to move away from this over investment in fossil fuels ,I think he is expressing a desire for a healthy economy and to avoid the kind of crash that the sub-prime mortgages caused the credit crisis and great recession. We have sub-prime carbon assets and as a percentage of the economy, they are more here than anywhere else," he said.