Nowhere is the new politics more apparent than in energy policy, but it's not all sweetness and light. On Wednesday morning industry secretary Alistair Darling warned darkly on BBC radio that the lights would go out if the SNP maintained its antipathy to nuclear power. It was irresponsible, he said, to rule out a new nuclear generation when there was no evidence that renewables could fill the energy gap.

But over the next seven hours, the lights went on at the Department of Trade and Industry (DTI). In interviews that afternoon, Darling discovered that the issue of nuclear generation was academic'' as Torness would be around longer than Alex Salmond. So why the change in tone?

Well, Scottish Labour decided it could no longer defy Scottish public opinion and the arithmetic of the Scottish parliament by doggedly demanding that there should be more nuclear power stations in Scotland when there is no demand for them. No new nuclear power stations are likely to be required here until at least 2033 if, as even the Greens now accept, the lives of Torness and Hunterston can be extended. That is plenty of time to bring on renewable energy.

During Wednesday's Holyrood debate on legislative priorities, Jack McConnell effectively rejoined the anti-nuclear consensus by not objecting to Alex Salmond's anti-nuclear statement. But why did it take McConnell so long to bend to the inevitable? It's not as if British Energy (BE) was eager to build any new stations in Scotland.

BE wants the next generation to be in places such as Brighton and Oxford, nearer to the demand. Now that the citizens of the English heartlands realise the successors to Three Mile Island and Chernobyl are going to be on their doorsteps, rather than in remote'' areas such as Scotland, we shall see whether there really is support in Middle England for nuclear power.

With 25% of Europe's wind and tidal power on Scotland's shores, waiting to be exploited, it would be perverse to pour money into new nuclear plants when there is already 20% surplus nuclear capacity. The strange, and tragic thing about all this is that Labour had to lose an election to come to terms with this reality. When he was First Minister, McConnell had been forced, against his own inclinations, to accept the No 10 line that Scotland could not be excluded from the new nuclear future.

Scotland now accepts that renewable energy is the cost-effective future. But still the UK government is unable to come fully to terms with the demands of the renewable future, as we discovered last week when BP pulled out of the first commercial carbon capture power station in Aberdeenshire.

BP had invested $50 million in this project at Peterhead to build a power station run on hydrogen from natural gas and store the C02 produced in a spent oilfield. The government thought BP was in for keeps. But with Lord Browne's departure, enthusiasm for making BP Beyond Petroleum'' has waned, and the prospect of keeping the Miller field open another year while the government organised a competition for the project funding was too much. BP took its ball away.

The SNP government is naturally livid, despite the propaganda bonus for independence. Salmond is attacking Darling and Co for incompetence and selling Scotland short, so preoccupied with the case for new nuclear power stations in England that they failed to keep their eye on the renewable ball in Scotland.

There is clearly some truth in this. Because the UK government is committed to nuclear energy, it is less responsive to other projects. The BP plant would have required substantial public funding, which may now find its way into subsidising nuclear power stations in England.

As for BP, it does look as if it used the timing as a convenient excuse for dumping a project that had cost it a lot of money. Equally, the UK government has a case in arguing that it could hand over money to BP only after other firms had been offered the chance to compete. But it doesn't really matter who is to blame. What matters is to get the project going again, and nothing is being done in this regard, essentially because there is no machinery to do it. In the past, McConnell would have rung Darling to say: Look, this Peterhead business is not on ... Nats would have a field day ... CO2 obligations ... etc ...'' Darling would then have rung Tony Blair, who might have rung BP board members. Having the PM on the line concentrates the mind wonderfully. But right now no one is telephoning anyone, and the result is that Scotland - and Britain - is liable to lose its lead in a world breakthrough energy technology.

This is not the time for playing the politics of nations and regions, but for banging heads together. If the industry secretary cannot summon the will, he should call for the Great Clunking Fist. The PM in waiting should waste no time in ringing up BP if he wants to ensure that the new politics of Scotland will not be the politics of independence.

For there will be a lingering suspicion that the real reason this energy project went west is that Labour in London is unwilling to work constructively with a nationalist government in Scotland. That will be hugely corrosive to the integrity of the very United Kingdom Gordon Brown wants to keep united.