There are some treasures but they moulder in poky cases under low-budget film noir lighting.If the great and good wave the Spiral through, they will have cattle- prodded South Kensington’s architectural heritage into a kind of fourth dimension. The variable geometry of the Spiral, its three-metre-wide exterior ceramic tiling and look-no-hands engineering calculations by Ove Arup that have used Nasa computer technology, is poised to create a pounds 75m craft object that will seem to have been beamed in from the late 21st century.The design was developed after a careful study of the relationship between Cromwell Road and the roofscape – what pedestrians will see, on one hand, and the building’s internal functions. His decision to install gas jets in a later building was typical: he wanted to attract visitors of all classes in the evening; the museum, he said, was to be “a powerful antidote to the gin palace”.The V&A Spiral may appear wild – one sympathetic critic described it as “an explosion in a cardboard box factory” – but its creator is no feral iconoclast or closet sculptor. This can be demonstrated by examining the considerations that drove the design of the Spiral and rolled the opening credits on what has become Vicky and Al’s Big Adventure.According to the V&A’s major projects director, Gwyn Miles, Libeskind got the nod because his building made the hugely avant garde statement required – and because it met every practical demand of the brief in detail “We know the Spiral will work,” said Ms Miles “It’s spot on. He listened to what we said better than the other architects.”That the V&A could even consider a new building as radical as the Spiral has much to do with a “conscious decision we made about 15 years ago to go back to our roots and make sure that we did collect the contemporary”.Since then half the V&A’s annual pounds 800,000 purchase grant has been spent on contemporary material. Architect Ian Simpson said: “It’s not a modern building, but a piece of sculpture that looks dated already.” Another, Ben Derbyshire, said the design filled him “with dread that we can seriously consider such a building in our midst”.Of course, the V&A’s history is littered with brouhahas, starting in 1856 when the Department of Practical Art built the South Kensington Museum – two rather lumpen prefabricated iron structures which looked like the barrels of huge steam engines and were promptly dubbed the Brompton Boilers.The sledging cut no ice with Henry Cole, the museum’s brilliant eminence grise who understood something more important: that even in the mid-19th century, arts and craft had to compete It needed a modern approach. Had it been just a neutral box it would never have got built, that’s for sure.

There would have been no reason to do it.”And it was this same intellectual rigor and passion that carried the day for Libeskind’s V&A Spiral design, seeing off aesthetically mannerly entries from gilt-edged competition including Sir Norman Foster.When the Spiral’s design was first publicised it received predictable condemnation. Virtually every line, every window, every dimension and space is vectored into those 1,050 Jews who perished or were exiled.And so Berlin’s Jewish Museum is a kind of rune, a repository for what Libeskind calls “the things that never came to fruition, the traces that were never born in this city”. In some of the spaces, particularly the voids, there is a leaden sense of the capture of time that stopped in the mid-1930s when Jews “believed themselves to be carriers of the German idea of culture They created the idea of modernity. Libeskind found out where they had lived and plotted the lines from their homes so they ran through the museum site to create an “irrational matrix in the form of a series of squared triangles yielding reference to the compressed and distorted star, the yellow star that was so frequently worn on this very site”.He used this extraordinary web of intersections to plot not only the museum’s horizontal planes, but its vertical and angled ones, too. And it was fatal”.There are other complex ideas immured in the Jewish Museum: the relationship between what cannot be represented in architectural space, and the architecture itself; what Libeskind described as “the invisible city that’s all around it, the city that’s still there and everybody comes and looks for it”, and finally, Schoenberg’s uncompleted opera in which the third act, written after his exile, had a libretto but no music.”I fought for it because I do think the citizens, the taxpayers, understand it. Nothing is normal, yet there is an overwhelming sense of a precise intent Something is there, waiting to be found …

or lost.And then, Libeskind’s revelation, the touchstone for what may be the only museum in the world that is itself Exhibit A. He selected 1,050 Jews who had formed the weft of Berlin’s pre-war tapestry of arts and sciences – Jews who invented theGoethe Society, Jews who considered themselves so utterly German that their families’ tombstones in the Weisensee cemetery carried gothic rather than Hebrew script. Attracted to the mystical and to forces of intuition, Libeskind remains utterly dominated by the need to produce works that are perfect expressions of intent and function.Beyond the tatty hoardings in the Lindenstrasse, the sunlight sheers off the building’s strangely massed facades and angled windows. Its visual signals seem not so much mixed as from an unknown place. Initially, the Jewish Museum is beyond description; it demonstrates no known style.Walking up the dark, oddly angled underground ramp one is confronted with two corridors angling away in an ambiguous V – which way ought one to go? – and the first of the museum’s seven voids. And, as with the exterior, there is an unsettling sense of the ungraspable in the oddly angled and linked spaces in black, grey or white. Thousands of punters (“They’re not art critics, they’re just normal people,” said a beaming Libeskind) have been shown through its strangely intersecting galleries and apparently inexplicable concrete voids.Mr Pot, he is not.

Compact, dressed in the international architect’s regulation matt black, hands always on the move, discourse and asides flying out like doves from a magician’s sleeve, he is simply the personification of his architecture. The 52-year-old Polish- born polymath has, for example, been branded as a destroyer of Berlin. Yet the “destroyer” seems to have an army of unlikely followers. The Jewish Museum has unexpectedly become a leading attraction. It earned Daniel Libeskind praise and vilification in equal measure – and the put-downs were, at times, monumental. On the one hand, the idea that memory can be a “horrible cabinet of curiosities”, and on the other, his exquisite remark that “separation penetrates the disappearing person like a pigment and steeps him in gentle radiance”.That controversial ingot is Berlin’s Jewish Museum, due to open this summer. It’s a sunny Saturday afternoon; youngsters are languidly playing opposite the city’s Stadt Museum.