Now, the intervention of Libeskind in Exhibition Road may well be interesting, with its pile-up of jagged, angular planes contrasting violently with the sober Classical facades either side, but that is not the point. His extension to the Berlin Museum is certainly an extraordinary and most moving structure, really a piece of Expressionist sculpture, but do not suppose the members of the royal borough's planning committee were interested in that or really made any careful study of the V&A's plans to see if the thing might possibly work. All that mattered was the name, the label, the designer. Libeskind - whether deservedly or no - is now among the elect. He is a genius, and every one of his creations must be a masterpiece. And no one dares oppose the building of one of those: it would clearly be social death. Even English Heritage feels obliged to "welcome" the design although it is none of its business, which is with the merits of old buildings, not new ones.
Architects used to be dull men wearing bow-ties and smoking pipes who would attempt to salvage something worthwhile from the bullying of insensitive clients. Now everything has changed: glossy magazines, architecture pages in newspapers and television, together with a paucity of genuine criticism, have made a handful of successful ones into stars, whose lives feature in the style pages, who wear designer clothes and who - if they are British - collect knighthoods and even peerages. It is the triumph of the Modern, of the glamour of the avant-garde, although there is now nothing remotely avant-garde or anti-establishment about Lord Rogers of Riverside with his fashionable restaurant in Hammersmith and his close friendship with Peter Mandelson and Tony Blair. What could be more a product of narrow official patronage than the boring and pointless Millennium Dome?
I first realised that a handful of architects had broken through the stratosphere and were simply above rational criticism when the new terminal building at Stansted Airport was greeted with ecstatic praise by absolutely everyone, even Sir Peregrine Worsthorne. Image and label were everything. Actually, the new building is an elegant high-tech shed, but the airport itself is not particularly well planned or efficient. But the point was that it was designed by Sir Norman Foster, who simply can never make a mistake in the eyes of his admirers. With his huge office and international connections, he can do no wrong, so - to create the right image - the Germans get him to revamp the Reichstag in Berlin. And when Glasgow wants a new conference centre, it goes straight to Sir Norman, ignoring both local talent and the fig leaf of a competition. In consequence, the city got a cheap and nasty version of the Sydney Opera House designed by somebody in the office. Now Gateshead wants one too. These architects form an elite, a club, one might say a mafia, doing each other favours and awarding each other prizes: the Pritzker, the RIBA gold medal, etc. So no surprise that this year's Stirling prize has just gone to Sir Norman Foster for his Duxford hangar.
Not that becoming a superstar architect is easy. It needs years of assiduous self-promotion, and not all make it. Take Zaha Hadid, for instance. Her design for the Cardiff Bay opera house was a masterpiece of so-called Deconstructionist architecture, all jagged angularity and dramatic gesture, and was acclaimed by the great, the good and the London architectural mafia as a work of genius. Yet, unaccountably, the Welsh did not want it, and they have been regularly condemned as philistines ever since. Was the design any good? Who knows? Who cares? The drawings were carefully stylish and opaque, and two professors of architecture admitted to me they found them incomprehensible. If you bothered to study them closely, it was just possible to discern an unremarkable and rather depressing disposition of internal space. At that stage Hadid had built only a celebrated non-functioning private fire station in Germany; now, at the current fashion show at the Hayward Gallery, London, she has shown herself to be a pretentious and mediocre exhibition designer. But I am sure she'll make it in the end.
Museum curators seem particularly vulnerable to the cult of the superstar. No museum or art gallery is now complete without a spectacular extension designed by a famous architect, and the rich patrons who dominate the art world in Britain are happy only with a famous, approved-of name. Securing a radical design seems to be a higher priority than a suitable setting for objects. The model here, of course, is the new art gallery in Bilbao, that deliciously arbitrary confection of shiny metallic surfaces designed by the Californian architect Frank Gehry which has received so much (gushing) publicity that it has put the faded Spanish town on the international map. Alan Borg clearly hopes that what Gehry has done for Bilbao, Libeskind will do for South Ken.
Very different is the cool, not to say frigid, reinterpretation of the cliches of pioneering white Modernism purveyed by another American, Richard Meier, who has collected museum commissions all over the world, culminating in the multi-million-dollar Getty Center, that art fortress on the top of a hill outside Los Angeles. Considerably more interesting is James Stirling's Neue Staatsgalerie in Stuttgart, a genuine masterpiece by the britischer architekt, as that car advertisement puts it. Alone it has put that much-ravaged city back on the map. But are any of these buildings any good for their purpose? Well, some are and some are not. But that is beside the point: what matters is the building as a work of art, not the works of art they are meant to display.
Now, with a government obsessed by image and fashion, and with lottery money (sometimes) available for a big gesture, such buildings threaten to become the norm rather than the exception as the imperatives of the smart designer building override old-fashioned considerations of brief, practicality and budget. The supreme example, of course, is that round plastic tent in north Greenwich, a tribute, above all, to the superstar status of its ostensible designer, Richard Rogers, aka Lord Rogers of Riverside, that relentlessly modish figure who now exercises more political power than any architect since Albert Speer.
But there are other examples. It is indicative that the New Labour government has imposed new buildings on both Scotland and Wales; in each case, the parliaments they are to house have yet to exist and so cannot decide what building they would really like and, in each case, there is a distinguished historic building which could be used, if only as a temporary measure. So Edinburgh will now have the composition of "upturned boats" by the Catalan architect, Enric Miralles - a rising superstar - while Cardiff will be graced by another masterpiece by (surprise, surprise) Richard Rogers.
So how did we come to this state of affairs in which the new building - as landmark, as image, as symbol of modernity, as expression of individual genius - is much more important than the function it is meant to serve? I blame the French. It all began with the grands projets, those attention- seeking monuments imposed by presidents obsessed with their place in history. So we had the Centre Pompidou by Renzo Piano and Richard Rogers, a structure which was all show-off and which, less than 30 years on, is being reconstructed at huge expense. But worst of all is President Mitterand's new Bibliotheque de France by Dominique Perrault in which, in defiance both of cultural imperatives and common sense, precious books are hoisted into four glass towers while readers are forced underground. This famous building (whose staff are now on strike in protest) makes the new British Library by Colin St John Wilson seem a model of sanity and practicality in comparison.
Is it possible to escape the embrace of the cosy world of the superstar and secure a museum extension, say, which modestly addresses practical problems and yet manages to be distinguished architecture? Surely it is, and the model should be the Burrell Museum in Glasgow, a truly innovative but undemonstrative building widely and rightly praised for the beauty and sensitivity of its housing of Sir William Burrell's collection of art and antiquities. The design for this was chosen in a genuinely open competition almost 30 years ago, and the winners were three young outsiders from Cambridge: Barry Gasson, John Meunier and Britt Andreson. Who has heard of them? Yet the building remains a triumph. I suspect that the boldest and most truly radical action a museum director could now take would be choose the design of a new building by architectural merit alone, ignoring the mischievous stare of the designer architect label and the cult of the superstar which are trivialising the Mother of the Arts.