He's not a household name; he's not up there in the public mind with the Mandelsons and Blunketts and Mowlams but in eight long years of Labour government, Elliot Morley has been uniquely successful: he is the only minister, apart from Tony Blair and Gordon Brown, still working in the department he joined when Labour was elected to power in 1997.

First, he was in the old Ministry of Agriculture, Fisheries and Food (Maff), and now he is in the super-ministry that absorbed it in the wake of the foot-and-mouth crisis in 2001, the Department for Environment, Food and Rural Affairs (Defra).

The quiet, burly Scouser has progressed steadily with an unspectacular but very sure touch, until now, as No 2 to the Environment Secretary, Margaret Beckett, he has reaped the reward for such reliability: a very large political hot potato has been dumped in his lap.

They don't come much hotter than Labour's climate target. No government likes admitting that one of its key policies, the subject of endless pledges, seems destined to hit the rocks, especially when the policy is in an area that the Prime Minister has made his own; and with Tony Blair's high-profile campaign to fight climate change, that's just what is happening.

Eleven years ago, the Labour Party, then in opposition, promised it would cut back the UK's own emissions of carbon dioxide (CO2) " which is causing global warming with potentially disastrous consequences " by a hefty 20 per cent by the year 2010.

In three successive general election manifestos, 1997, 2001 and 2005, and in many other ministerial speeches or platform pronouncements, that promise has been solemnly reaffirmed. It has put a particular shine on Labour's green credentials, because it was over and above what was required.

For Britain has two targets for cutting its greenhouse gas emissions. The first is the one mandated by the Kyoto protocol, the international climate treaty: to cut emissions from a 'basket' of six different greenhouse gases, including CO2, by 12.5 per cent by 2010. The good news is that we are almost certain to meet that target, largely because of the 'dash for gas' in the 1990s, when many coal-fired power stations were replaced by gas-fired units,

The 20 per cent target is different: an entirely voluntary commitment of Labour's own making. But it has assumed an enormous importance in the past two years because it has become clear that, on present trends, it is going to be missed by an embarrassingly large margin.

UK emissions of CO2 in 1990 were 161 mtC (million tons of carbon), and 20 per cent below that figure is 129mtC " there's the target. In 2004, C02 emissions were down to about 155mtC " about 4 per cent below 1990 " and, on present Government projections, will be about 140mtC in 2010, about 13 per cent below the 1990 level " instead of the 20 per cent the Government has been promising till it is blue in the face.

Get out of that one, Tony.

No matter that, as Mr Morley points out, to get your CO2 emissions down to 13 per cent below 1990 levels five years from now is probably doing better than any other industrial nation.

Politics is about appearance as much as reality and, at the very moment when the evidence of climate change is piling up, at the moment when Tony Blair is seeking to lead an international global- warming crusade, people can point to his domestic climate policy, and say it's a failure.

That's the hot potato Mr Morley, the 53-year-old MP for Scunthorpe, has been given: to turn things around and put policy back on track to meet the target after all. He has been charged with a root-and-branch review of the Climate Change Programme, the long list of measures intended to cut Britain's output of CO2, from energy efficiency agreements with industry to insulation projects for homes. A reflection of the job's importance is that he has the title of Minister for Climate Change (and Environment) " the first such title, he thinks, anywhere in the world.

Look him up on the Defra website and you will find he has 18 separate defined responsibilities, from floods and coastal defence to radioactive substances, but the review, he says, is taking up nearly all his time.

His first comment on the job is that it is possible. 'I think, if I'm being honest with you, we're going to see a bumpy ride on this, because the figures [for emissions over the next few years] are going to go up and down. But I think we can get a downward trajectory that will get us to the 20 per cent.

'It isn't going to be easy, and I wouldn't pretend otherwise. But I think it can be done.'

Progress towards the target has gone off course for two main reasons, he says. The first is the high price of oil, which has meant that coal " which produces the most CO2 " has become a cheaper option for power generators.

The second is the increased economic activity of Britain's recent, unprecedentedly long period of economic growth has meant many more movements in the transport sector, with transport CO2 emissions rising very fast. So, for the past two years, the UK's total emissions have risen rather than fallen.

Mr Morley doesn't have the option of a magic answer, a technical fix such as a massive increase in nuclear power, which Tony Blair is eyeing as a long-term weapon in the climate fight.

Nuclear, which does not produce CO2, is no help towards the 2010 target because even if a dozen new atomic power stations were started tomorrow, they would not be on stream in time. And, anyway, as is clear from Mr Morley's careful comments on the atomic option, he is not a nuclear fan. Speaking personally, he says, he feels 'the great Achilles' heel of nuclear power is its cost'. The sums involved, especially when decommissioning of stations is factored in, are enormous, and the billions of pounds involved could perhaps be better spent on other forms of energy, such as renewables.

Rather, Mr Morley has to take existing policies and tighten them as much as he can. There will be some bold proposals in the review, he says, such as the biofuel obligation, and about which he is enthusiastic " 'It would save us a million tons of CO2 every year. Just that' " and the use of new technologies such as carbon capture and storage, by which the CO2 emitted by power stations is trapped and sequestrated deep underground.

But much of it will be making current policies work better, and sometimes, that will be expensive, for a relatively small increased return.

The key difficulty is that everything has to be agreed across Whitehall. He wants to increase the tax on gas-guzzling cars? That's the Treasury. He wants to tackle rapidly rising emissions from aircraft, because of the cheap flights bonanza? That's the Department of Transport.

He wants new technology for power stations? That's the Department of Trade and Industry. 'I do need to emphasise that while we are taking the lead on this in Defra, we can't deliver this on our own, and to deliver this 20 per cent target every government department has got to make its contribution.'

The Whitehall ride has already been bumpy. The Independent has learnt, from sources outside Defra, that recently a determined attempt was made within government " in which the Prime Minister's industry policy adviser, Geoffrey Norris, was a key figure " to have the target scrapped, on the ground that it was proving too much of a burden for industry.

When I put that to Mr Morley directly he was caught off guard for a second, I asked him: 'Has anybody ever suggested, in Government, that the 20 per cent target should be abandoned?'

He said: 'Er ...' Then he laughed. Then he said: 'What can I say to this, really?' Then, fluent as always, he responded: 'I think it's fair to say, that in terms of all government policies ... there is always discussion within government about whether they're realistic, about whether the costs exceed the benefits, and whether there are alternative approaches " and those discussions have applied to the target on climate change as they have to every other policy.'

But asked if he would accept that if the Government did abandon the target, it would look very bad, he replied: 'Absolutely. And the Government is not going to abandon the target. Let's be absolutely clear. The Government is not going to abandon the target.'

In many ways, Mr Morley is the ideal man to pursue it. A passionate birdwatcher since boyhood, he has the most impressive green credentials of any Labour minister " he has been a member of the council of the Royal Society for the Protection of Birds " and it is widely accepted that his heart is in the right place. Whether that will be enough to perform the biggest political conjuring trick of recent years, and rescue Labour's flagship policy, remains to be seen.

The CV

n Born: 6 July 1952

n Education: St Margaret's High School, Liverpool; Hull College of Education (B Ed)

n Family: Married in 1975, one son and one daughter

n Career: Head of special needs, Greatfield High School in Hull from 1979 to 1986; councillor on Hull City Council from 1987.

Elected Labour MP for Glanford and Scunthorpe (from 1997, Scunthorpe)

1989-1997: Opposition frontbench spokesman on food, agriculture and rural affairs

1997-2003: Parliamentary under-secretary at the Ministry for Agriculture, Fisheries and Food (Maff), then Defra

2003- Minister for Climate Change