She invited a few of them in for supper the other day - the five surviving prime ministers from her 50 occasionally glorious years. Polite chitchat and photocalls. But what does she really think of them, and their five dead predecessors? How do they and their policies look from her seat in the royal circle? And "circle" is the word. The big contortions, of course, are the most obvious. She began with a Conservative PM making statesmanlike speeches about the need for European union (with Britain, as usual, somewhere adjacent to its ventricle regions) and a Labour party viscerally opposed. She winds up five decades later with a Labour PM piping Euro-rhetoric from every available artery and a Conservative would-be prime minister whose hair would stand on end at Churchill's visions, if he had any. (Hair that is, not visions.)  But great upheavals are a natural part of politics: it's the detail of the years from Butler to Byers which is more dismaying. Why, Iain Duncan Smith inquired recently, "are we still running our public services in the same ways we did after the second world war?" This is the 21st century, he said. "We've lived through the cold war, the development of nuclear weapons, the fall of the Berlin wall and the rise of the internet." But health and education and the rest were still "Clem Attlee" stuff, frozen in time and immobility. Or so he seemed to think. In reality the record is far worse than that. It is a long and costly amble round the houses, a potter of constant change in order to get back to where we (and Her Majesty) started.  IDS - because he's Winston's current heir and thinking aloud for his living these days - is the obvious marker for half a century; but, to be honest, new Blairism would serve almost equally well. Just consider...  British education used to be local and wholly devolved, run by school boards in your home town, not ministries in London. The minister of education and his Sir Humphreys could jawbone but not prescribe; they worked - wait for that word again - through "circulars" bearing advice from on high. They were rarely taken much notice of.  Who changed all that? A bit of Butler in 1944; a pinch of Crosland through the 60s. But I remember the 80s best, and sitting with Kenneth Baker in his shiny ministerial limo while he explained the wonders of a national curriculum. A pox on sloppy schools and sloppy teachers turning out kids who couldn't read because they and their unions defended failure: a chance, at last, for the centre to demand something better - true equality of opportunity - with means to deliver.  It sounded good. And now? Mr Duncan Smith wants (somewhat mystically) to guarantee equal opportunity another way: by trusting heads and teachers, by getting centralised government and politics out of the act. "Trusting people is the modern way," he says - as opposed to the old way, when we absolutely knew that the people who mattered couldn't be trusted. "It is organisations operating on a human scale that succeed."  So, in IDS-speak as well as Milburn-speak, the doctors and nurses become not merely the front men and women of health, but its front line of decision-making again. Just as they were before Elizabeth married Philip, and Nye Bevan, after the most draining of fights with Consultants Incorporated, founded the NHS. Once the NHS answer was centrally set targets delivered by an efficient management (mostly nurses seeking a better salary and career). Then we had trusts and more management. Now we may be going back to men in white coats running everyone's lives   out of their own back pockets. Once we put our faith in waiting lists. Now these are suddenly tawdry devices.  Crime? Bobbies on the beat or in their pandas? Dixon of Dock Green or Z-Cars? We've oscillated back and forth over the years.  Devolution? "Switzerland is a very small country," reveals IDS, "yet it retains a vibrant and vital local tradition through its cantons." Does that mean that today's Conservatives want stronger, more independent local administration - Thatcherism in reverse? Er... yes and no. Not "regional assemblies which don't drive power down from Whitehall but strip it from local communities". They, apparently, mean "more centralisation, not less". Stronger local councils, then, with drastically increased revenue-raising capabilities? Er... no and yes. City mayors like Rudy Giuliani, "who turned crime around because he had the authority to do so"? Don't begin to explain that.  The difficulty for the Tories is that there's virtually no social policy where they haven't turned turtle (often many times) through the past 50 years. Which secretary of state for education saw the greatest ever number of comprehensive schools created on her watch? Yip, Mrs T, the same lady who put her name to the Single European Act. A life of ever-increasing circularity. And the difficulty for Labour is turning out to be much the same.  Here come the new super-ministries like transport and local government. There, barely a year later, they go again, dragging the remnants of their super-minister with them. Watch our latest patent variant on NHS internal markets come and go and come again. Here's what Roy Jenkins used to believe about penal (and asylum) policy - and here's the Blunkett version.   There is, to be sure, some progress. Once in the 50s, Harold Macmillan made his reputation because he "built more houses"; now ministers don't "build" houses any longer because it's their changed job to make the trains run on time. Once upon a more baleful time, the Ministry of Labour provided the most gruelling test in town; now it is called employment and nobody quite remembers whose wing shelters the remnants.  But on the main events, Your Majesty, on the big intractables like the hegemony of the Treasury that Harold Wilson tried to destroy with his Department of Economic Affairs and a deputy prime minister in charge? Ah! deputy prime ministers. They come and they go, too. The promise is always of progress. The delivery is always best suited to those with short memories and smaller expectations.  Only one thing, it seems, remains constant: occasional republican chuntering about tax holidays for happy monarchs, about duties which pay nothing at death. Willie Hamilton of beloved memory used to sing that song; other paler shadows have taken up his refrain. But nothing happens, Your Majesty, nothing at all. One circle that's never squared.