There was once a certain kind of child who would collect stamps, or gather the money that relatives brought back from foreign travel, and dream about what each piece of paper represented, where it might have been, who had touched it on its journey round the world. For that child, a stamp, a banknote were small passports to an exotic otherness. Or maybe they were instruments connecting cultures. That's how Mary Katrantzou thought of them. She loved the stories they told. As borders changed and currencies became obsolete, stamps and banknotes lingered as tokens of the past, literal souvenirs of the values of other, lost cultures.

All the romance, melancholy, and beauty of those ideas were swept up in Katrantzou's latest collection, an absolute fashion tour de force. She's already proved she can make a ravishing print out of almost anything, and she has applied those prints to some extraordinary silhouettes, but form and content blended so effortlessly today that this felt like the point she'd been aspiring to since she started. It helped that stamps and banknotes have an innate two-dimensional symmetry that loans itself to abstraction in accessible shapes. And Katrantzou's shapes today were noticeably direct: A-lines, shirtdresses, shifts, and sheaths, offering ideal canvases. A stamp's serrated edges, for instance, provided a striking geometric border down the leg of slimline trousers. And the whorls and spirals of a banknote provided a luxurious pattern for a pantsuit in midnight blue brocade, especially when shot through with darkly sparkling Lurex.

That particularly stunning outfit crystallized just how refined Katrantzou's eye has become at abstracting pure form from her inspirations. But she has also mastered her materials to a quite ingenious degree. The finale featured one-of-a-kind pieces that paired metallic brocades and Swarovski crystal mesh printed with banknote designs. The process was almost impossibly complex, but the result was pure poetry, suggesting the golden shimmer of Byzantium. At the other end of the scale, Katrantzou worked with denim for the first time. Those pieces came at the beginning of the show. Suffice it to say they were scarcely denim as we know and recognize it.

Alex Fury's show notes referred to "the pure cultural capital" generated by Katrantzou's alchemical transformation of her subject matter. The soundtrack made the point a little more straightforwardly when, at one point, cash registers rang out. How often will this collection be defined in the next while by one word: ker-ching?