That it won't, can't, happen, is one reason why Walden announced at the weekend that he is standing down as a Conservative MP. But this has been a long time coming. He is adamant he has nothing but admiration for his overworked, underpaid and brutally overexposed colleagues in the present government. In 1987, he now admits, he did not tell the whole truth when he resigned as Higher Education minister for personal and family reasons. The family reasons were certainly true: after a career as both a Foreign Office diplomat and a politician, he wanted to see more of his teenage children. But the personal part was a dawning realisation that British politics is increasingly, as he put it to his constituency chairman at the weekend, about the "management of illusions".
Approvingly, he quotes Edward Luttwak's maxim that the era of geo-politics is over, replaced by geo-economics. Not a field, he says drily, in which "we have been particularly pre-eminent". But the failure of the British political system to grapple with our lack of economic distinction is underlined for him by the way in which the adversarial, class-based House of Commons increasingly consists of "an auction of promises which it is becoming more and more impossible to deliver".
What are these illusions which party politics are so good at managing?
First, there is the illusion of state dependency. Walden finds it hard here to fit into the "left-right compress". He believes in a quantum rise in public spending on education, including state nursery education for every child from the age of three. He has long advocated the gradual seduction of the best of the private school system into the state sector, believing that as a country which will shortly be without assets, "we have only our wits to live on and we'd better start sharpening them". But on the welfare state he is more radical than almost any leading figure in the Tory party, believing that voters will have to choose between the long- term social and economic prosperity offered by an education system that works and the "middle-class pin money" of child benefit.
The NHS remains an "important illusion", too. He supports the Tory reforms, as far as they go, because they help to squeeze more out of the system. But he warns: "I do not understand how the people of Britain are going to go on supporting giving free medicine to the children of duchesses, free this and that to the elderly, however rich, child benefit and so on. No one wants to say this because both sides of the House of Commons have the middle classes in their sights. The Commons leads to a system of preserving myths."
VAT is another case in point. Both sides know, he argues, that because of the economic and political impossibility of raising income tax, there should be VAT on everything, probably at a lower level. "You can't do that because of some ridiculous Thirties hang up about barefoot children. So the subject can't be discussed."
An even more outstanding example of unspoken fiscal consensus is mortgage interest tax relief, which he alone among Tory backbenchers advocated abolishing in the Eighties at a time when every intelligent politician except Margaret Thatcher knew he was right. This peculiarly British belief that the British homeowner has the right to watch his house grow steadily in value hits a particularly raw spot with Walden. He knows, of course, that in the present climate it cannot be chopped at once. But he says: "It's not just financial; it's more fundamental than that. It is this culture of illusions. The British can turn their backs on the world and watch the price of their houses spiral up and buy a Honda with the proceeds."
The inadequacy of an adversarial House of Commons - whose "sanctity" is a matter of deep suspicion rather than celebration for Walden - is nowhere better illustrated than in debate on the economy. The standard procedure for Prime Minister's Questions is that John Major boasts of the recovery, and the Opposition says "absolute rubbish". Hence his fantasy that politicians might risk telling the truth to their electors, who, argues Walden, would cheer to hear it. "Churchill once said the news from France is very bad. You can't do that now. You can't say, for example, that the news about the economy is very bad. And they used to use words of more than one syllable and I don't think people are alienated by that." That is not to say that all the electorate is super-intelligent. "But I think they are a bit sharper than we give them credit for."
He clearly rates Tony Blair (as Blair is reputed to rate him) and commends him for breaking the normal rules by meeting him to discuss his plans for readmitting the old direct grant schools back into the state sector. But he takes the fairly conventional view that Labour's socialist tail will drag its social democrat leader back from doing what he will want to do. And it would take a lot more than he foresees happening to stop him voting Conservative.
Indeed, he does not believe that in opposition the Tories would implode under the weight of the right. He is not himself a Euro-enthusiast: he was doubtful about Maastricht and is even more so about the single currency. The Euro-phobic wing of the party he sees, however, as using Europe as a scapegoat for Britain's home grown problems - and threatening to ignite xenophobia. They will not succeed: "Their fox is going to be shot. What some of our chauvinists are about is trying to find a replacement for the Cold War. There is a convenient enemy because a lot of the Brussels proposals are nonsense." But he believes the French will be the brake on further integration. "A country which lets off bombs off lovely native islands to demonstrate her independence is not going to sell out to anyone." The IGC will therefore be a non-event, he predicts, and the right will find it difficult in opposition to maintain that Europe is a threat. "We have Murdoch and Conrad [Black] running a good deal of our politics. We have the New York Stock Exchange asking to buy bits of the City; we have a lot of our cars being made by the Japanese. We have big importation of American culture. And we say there's a threat from Europe."
This, Walden admits, is his incurably optimistic scenario: Labour will founder on a vain attempt to square the circle of lower taxes and higher benefits. On the back of middle class discontent there will then be the rebirth of a brave new Tory party, neither conventionally right nor left, but ready for the Walden package: higher spending on education and transport and an end to Miras and universal benefits - with a net shrinking of the public sector. And this time, at long last, Britain will "make it" into the post-imperial age.
He is almost studiedly vague about his own post-election intentions. He has no big money-making plans. He is chairing the Booker prize committee this year; he may collaborate with his art historian wife on a project or two. He will continue to write, but he won't even admit to planning the big book of his own that he must surely have in him. He is self-effacing about his relative lack of practical political skill. But in a way his departure is a testament to an anti-intellectual strain in British politics. Like Frank Field, he has been one of the most creative and independent- minded thinkers among backbenchers; if he drops out of politics altogether, it will be a loss to more than the Conservative Party.