London is swinging again.

The London Architecture Biennale took place for the second time last month--an extraordinary combination of events, temporary works, lectures, debates, installations and exhibitions. Norman Foster had to drop out of a sheep drive across his famous 'wobbly' Thames bridge, but Renzo Piano and Richard Rogers were there as substitutes. If that was the populist part of the event, the more serious activities involved masterplanning exercises, charrettes, designs from 80 overseas architects for London sites, complemented by plenty of parties. All this took place against a context of growing public interest in architecture and planning in the UK's capital, symbolised by a permanent new space to show what is happening, called 'New London Architecture', located at the Building Centre. Both this and the Biennale were the brainchild of sometime editor, publisher and exhibition organiser Peter Murray, who can be rightly proud of having injected huge energy into the London scene.

It is not simply the Biennale, however, which is evidence of London's claim to be the liveliest architectural city in the world. London-based practices are working internationally as never before. In New York alone in the last two months, Zaha Hadid has had a triumph with her New York Guggenheim exhibition (p88), while Messrs Foster and Rogers have both won commissions for buildings at Ground Zero. Work recently started on Chris Wilkinson's mega-tower in China; David Chipperfield continues to work globally; the sensational Madrid Airport by Richard Rogers Partnership has just opened (p34). Meanwhile Rem Koolhaas, for many years a resident in London, is finally designing here, with a media city masterplan and office headquarters.

Meanwhile, the Modernism exhibition at the Victoria and Albert Museum has been followed up by Future City, a marvellous show from the French FRAC Centre. This tribute to experimental and theoretical architecture since the 1950s, staged at the Barbican, is a reminder of how cities and countries go through cycles of energy and interest, not necessarily for reasons that can easily be analysed. The question the architectural community in London is asking is whether all this energy and talent will translate into a truly memorable 2012 Olympics. In this respect, Future City is instructive, emphasising as it does the power of the informing design idea to transform local environments, and entire cities at some psychological level. Achieving such transformations requires acts of imagination, not only from designers, but from clients, planners and funders too. The Olympic testing ground will validate or deny London's credentials to continue being the world's great hotbed of creative design.