Such has been the media furore over the return to Cabinet of Peter Mandelson that it seems almost sacrilegious to suggest that, once the dust settles, the return of new Labour’s prodigal son may be overshadowed by a mere reorganisation of Whitehall departments.

Yet while stories about how Peter patched it up with Gordon and what Tony thought about it dominated last weekend’s newspapers, it is the absence of energy policy from Mr Mandelson’s returned ministerial red box that has the potential to really make waves.

The fact is that successive Secretaries of State at the Department for Business, Enterprise and Regulatory Reform (and before that the Department of Trade and Industry) have failed to deliver their part of the Government’s promises to tackle global warming. They have often buckled in the face of the energy industry and business leaders, including elements within the Confederation of British Industry. With the fear-mongering line that 'the lights might go out, they push their own vested interests and ignore the needs of millions of poor people across the globe who will be the first victims of climate change, not to mention the citizens of this country.

The current situation in Haiti, where a combination of hurricanes and high food process have left hundreds of thousands of people hungry show the effects of climate change are already being felt by the poorest.

Ed Miliband, the first-ever Cabinet minister for energy and climate change, now has the chance to demonstrate how the Prime Minister’s promise at Labour's conference of “fairness at home, fairness in the world” can be turned from rhetoric into reality.

There can be no doubting the pressing need for change. In a week dominated by the growing global financial crisis, a couple of potential tipping points in the climate change debate have passed almost unnoticed.

On Tuesday, the committee charged by the UK government to examine climate change backed scientists’ call for an 80 per cent reduction in UK emissions by 2050. This was followed by a vote of the European Parliament’s Environment Committee to limit the emissions of new power plants, among other measures.

As Sir Nicholas Stern demonstrated so powerfully two years ago, the potential economic damage of climate change dwarfs even that of the current financial crisis. Yet UK government departments and corporations remain schizophrenic in their reaction to climate change. Oxfam’s report, The forecast for tomorrow reveals a country deeply divided between those who recognise the need for action and those who would rather pretend we can carry on with business as usual.

While the Department for Environment, Food and Rural Affairs, Greater London Authority and the Scottish Government, are all pursuing ambitious policies on climate change, BERR's approach to energy policy before the reshuffle is highlighted as one of the six organisations whose policies undermine the UK commitment to tackle the issue.

Faced with a potential reduction of electricity generation capacity of about 20 gigawatts by 2020, the department has appeared ready to ignore more than 30GW of renewable and gas-powered generating capacity under consideration or in development and plump for coal, without clear assurances of the potential for the as yet, largely untested technology for carbon capture and storage. A more recent change of heart by BERR on renewables should instead show the way forward.

The first litmus test of whether the Government’s reshuffle marks a sea-change in their approach to climate change or merely a rearrangement of chairs on the deck of a sinking ship will be the decision on plans by E.ON, proud sponsors of the FA Cup, to build the first new coal-fired power plant since a 23-year-old, bubble-permed Kevin Keegan scored a brace to help Liverpool to defeat Newcastle in the 1974 final.

Kingsnorth would have a dramatic and devastating effect on Britain’s carbon footprint; its annual CO2 emissions will be 7 million tonnes – more than the combined output of 30 developing countries. It would smash the EU’s proposed emissions limits. Kingsnorth and other coal-fired stations cannot be allowed to go ahead if the UK is to even come close to making the cuts in greenhouse gas emissions by 2050 demanded by the Government’s own experts this week.

Meanwhile, European governments, including the UK, will decide in the next few weeks whether or not to water down ambitious plans for tackling climate change and promoting renewable energy, voted through by the European Parliament this week.

These decisions will have a far-reaching impact beyond the levels of greenhouse gases emitted. Striking a deal at the international climate change negotiations this year in Poland and next year in Copenhagen, will require strong, demonstrable leadership from European governments that claim they are committed to playing their part in reducing emissions, if countries like China and the USA are to come on board. Britain and Europe cannot expect to take the lead at December’s critical negotiations in Poznan unless we can show that we are prepared to take tough choices and practice what we preach.

There is however hope for change. Despite the laggards like E.ON, Oxfam's report shows that we are also home to some of the world’s best, most inspiring progress in tackling climate change. National institutions such as Marks and Spencer, British Telecom and even the National Grid have led the way in taking concrete action to reduce emissions.

Gordon Brown showed the most political courage in his reshuffle, not in the way many have suggested by springing the surprise of returning Mr Mandelson to Cabinet, but in bringing energy and climate together under one roof.

Now he, and Ed Miliband must show even greater courage to swim against the tide of interests who would water down our commitment to reducing emissions at home and in Europe, and by doing so fuel the growth of a much greater and more damaging threat than the current financial crisis.

Phil Bloomer, Oxfam Campaigns and Policy Director