Mr Gordon Brown echoes what nice girls - in fact, most girls - used to say 50 years ago: "I love you, but not yet." Alas or (depending on your point of view) happily, it is hard to see how he will be able to change his line. There are no economic scientists labouring at Cambridge or the LSE who are on the way to producing a pill enabling this country to combine the benefits of a single currency with the privilege of setting its own rate of interest. They are not in the same position as those biological scientists in the United States who were able to separate the enjoyment of sexual intercourse from the risk of pregnancy. As Malcolm Muggeridge (the centenary of whose birth was celebrated last week) used to be fond of remarking to his friends: grasp that, dear boy, and you grasp all.
It may be, of course, that some bright spark will demonstrate conclusively that it is possible to operate a successful single currency while allowing the participating countries to proceed merrily along their own paths. Or we could be permitted to carry on regardless, with an opt-out on interest rates (partly justified by our strange housing market) comparable to our present opt-out on the euro itself.
Both these solutions are unlikely. The fate of our mortgage payers, a natural preoccupation of all UK governments, will be placed in the hands of Mr Wim Duisenberg and the European Central Bank. He does not, at first sight, inspire total confidence. He has too much hair to be a reliable central banker. True, his latest decision - to reduce rates to previously unknown levels - would please householders. At the same time it would inevitably lead to a sharp rise in the price of houses.
No more the days of Sir Edward George (about to be succeeded by "Professor" Mervyn King, as he likes to be called). The committee of workers, peasants and intellectuals known as the MPC would be abolished. We should all be in the hands of Mr Duisenberg or his successor.
But you never know. After all, the Bank of England was nationalised after the war partly to take interest rates out of its grasp and to place them with the Treasury. Successive Labour Chancellors would not have dreamt of handing them back. The Tories were divided about the idea. Then along comes Mr Brown, waves his magic wand and returns interest rates to the Bank in a gesture comparable to Sir Geoffrey Howe's abolition of exchange controls. What would have been denounced as a surrender to the sinister forces of City finance is now acclaimed as the wisest single action of the incoming Labour government. Could it be that the comparable transfer of power to Mr Duisenberg would come to be regarded in the same way?
What is clear is that it is never going to be precisely the right moment to join up. Mr Tony Blair will want to join when he thinks he can win a referendum, which is not yet. It is doubtful whether Mr Brown looks at matters in precisely the same way. Admittedly he is prepared to make all the right noises. Writing in The Independent on Friday Mr Robin Cook (who now seems to be writing almost as many articles as Lord Hattersley) welcomes profusely Mr Brown's expected intention to announce a "paving" Bill in the Queen's Speech for the referendum on the euro.
That will not happen till November. In any case, it commits the Government to nothing at all. It could lie on the statute book unused. With the Government's majority as large as it is, a Bill setting up the machinery for a referendum could be passed in days. A paving Bill is no more than a piece of public relations. It is surprising that a politician of Mr Cook's experience and acuity should have been taken in by it.
Besides, we have been here before. After 1997 an organisation was set up under the auspices of the Government ostensibly to urge our joining the euro. Mr Kenneth Clarke got into trouble with his party for appearing with ministers on the same platform. His Tory critics spoke truer than they knew. For the body in question was not really about the euro at all but about making somewhat vapid noises about Europe and, above all, accusing the Conservatives of wanting to take Britain out of the Union. There is no very convincing reason to suppose that the successor-organisation will be allowed to conduct itself any differently until such time, if it ever arrives, as Mr Blair decides he can safely hold his referendum.
We are now talking about the old referendum, the one on the euro. It was first promised by Mr John Major when he was Prime Minister to try to preserve some semblance of unity in his party. It was taken over by Mr Blair in opposition, though he did not have the slightest need to do so. His party was not divided as Mr Major's was. He simply could not bear to seem to be giving the Conservatives any apparent democratic advantage. The wretched thing has now been hanging over us for six years, longer if you include Mr Major's period; which, as old Euclid used to say, is absurd. It now looks as if it will be hanging over us for a few years more.
What could galvanise matters is that other referendum which (according to Mr Peter Hain) is not going to be held and has certainly not been promised, or not yet. This is the one on the new European constitution. Nothing in the past few weeks has been more striking than the way in which ministers, privately and in public, respectively treat the allegations about weapons of mass destruction in Iraq, or the lack of them, and the demand for a referendum on the European constitution.
Iraq they pass off with a light laugh. Who won the war? they ask. With the referendum, by contrast, they look apprehensive. Indeed, it is not going too far to say that a hunted expression crosses their faces. Even Mr Iain Duncan Smith succeeded in embarrassing Mr Blair at Prime Minister's Questions in successive weeks over the referendum; whereas last week, over Iraq, he hurt himself more than he did Mr Blair. Over Iraq Mr Blair is as shameless as a man trying to sell you the clock that he stole from your mantelpiece the week before; over the referendum he seems to be blaming himself for the existence of the body in the front parlour.
And yet he never promised such a referendum in the first place. It is not like the one on the euro. This may be part of the explanation. It is all so unexpected. It is unpredictable. And the demand is supported by so many unlikely people - by our most respectable columnists, for what they are worth, not to mention Mr Frank Field. There is something else. Europe tends to bring down Prime Ministers. It helped bring down the last two. Mr Brown is, we may be sure, well aware of this fatal characteristic.