Gordon Brown will today use his New Year message to broker a new "coalition for change" with Barack Obama on the economy, the environment and the war on terrorism.
In an attempt to make a decisive break from the Blair-Bush era of transatlantic diplomacy, the Prime Minister sets out the terms for the new special relationship with the president-elect ahead of his inauguration next month.
Despite the global economic storm, Britain and the US will work closely on tackling climate change, including a successor to the Kyoto Protocol at next year's Copenhagen summit, Mr Brown says in his traditional turn-of-the-year address.
Turning to Britain's handling of what will be confirmed as a recession early in 2009, Mr Brown promises that the Government will be the "rock of stability" on which people can depend. Invoking the fighting spirit of the Second World War, he says British people have the character and qualities to deal with whatever is thrown at them.
He takes a swipe at David Cameron and the Conservatives, whom he accuses of being the "do nothing" party on the economy, warning: "The threat that will come of doing too little is greater than the threat of attempting too much."
Mr Brown adds: "The scale of the challenges we face is matched by the strength of my optimism that the British people can and will rise to meet them – because we're not a do-nothing people."
The Government will continue to spend its way out of the recession, the Prime Minister makes clear, with another major injection of money on the cards. "The failure of British governments in previous downturns was to succumb to political expediency and to cut back investment across the board, thereby stunting our ability to grow and strangling hope during the upturn.
"We will eventually look back on the winter of 2008 as another great challenge that was thrown Britain's way and that Britain met; because we had the right values, the right policies, the right character to meet it."
Following President Obama's inauguration on 20 January, Mr Brown will travel to Washington in February for the first bilateral talks between the two leaders.
In April, London will host the G20 summit of industrialised and emerging economies, with the Prime Minister and President Obama in leading roles.
Next December, a major summit in Copenhagen will form the basis of the next generation of global measures to tackle climate change, to succeed the Kyoto Protocol.
Despite Tony Blair's close relationship with George Bush, the former prime minister was never able to convert the outgoing president to the fight against global warming. Mr Brown's aides are optimistic that the Obama administration will herald a transformation in how the world tackles climate change.
President-elect Obama has already set out his stall for a green White House, appointing the world's leading experts on global warming to central positions in his administration. One of his first acts on taking office will be a green economic stimulus package to create millions of jobs in home insulation and renewable energy.
Echoing the optimism of Mr Obama's "Yes we can" campaign slogan, Mr Brown says of fighting climate change: "I believe we can do it – and because we can, we must. The stakes are too great with our planet in peril for us to do anything less.
"I look forward to working with president-elect Obama in creating a transatlantic and then a global coalition for change."
Downing Street has dismissed speculation that Mr Brown will hold a snap spring election, and although one could be on the cards in June, he is expected to hold off until 2010. But as 2009 begins with the new Obama presidency, Labour and the Tories could enter a "phoney war" as they continue to battle it out over the economy.
Mr Cameron and Nick Clegg are also expected to focus on the economy in their New Year messages.