Has Manhattan lost its mojo?

The first time I went to New York, I was in my thirties. I'd never been anywhere so exciting, so mesmerising, so breathtaking in its man-made beauty. At that time, I really had only the Blackpool Illuminations - extremely impressive in their own way - as a point of reference in terms of a light show on a grand scale.

But that first sight of Manhattan after what seemed like an eternity snaking through faceless suburbs in a rolling traffic jam didn't just quicken my pulse, it completely captured my imagination. I've been to New York probably a dozen times since that inaugural trip, and never has it failed to deliver: invigorating and captivating, with a sense of otherness and more than a hint of danger.

But this time something had changed. Yes, I still love the yellow taxis, and the smoke rising from the streets like urban geysers, and the Chrysler Building and the Carnegie Deli, and all that restless humanity and..and..and. Plus, there was the bonus on my visit this week of seeing Woody Allen play clarinet, as he done every Monday night for the past 15 years, at the Carlyle Hotel. (I don't claim to be a woodwind specialist, but he seemed pretty damn good to me, contributing note-perfect solos with as much gusto as an old man could muster, preserving his energy by sitting there motionless and staring at the ground when not called upon to play.)

Anyway, the point is this: I ceased to be impressed by the energy of New York, I wasn't awestruck by its cultural, culinary and commercial possibilities, and I didn't find myself looking upwards and marvelling at its scale. I questioned myself. Was this about me, or was it about New York. Am I jaded? Or has Manhattan lost its mojo? The answer may be a bit of both, but there's another reason.

In the past, we'd compare technicolor New York with monochrome London. Now, it's completely the other way round, and New York didn't have me in its thrall this week because, frankly, it's not that special any more. In the (admittedly superficial and subjective) way that cities are judged, London is now streets ahead of New York as a centre of artistic invention and public enterprise.

Of course, both cities have their share of urban deprivation and inequality, but I often find myself walking through central London now and marvelling at its boldness, its sense of drama, its confidence in the way public spaces are used. I can't see the Trafalgar Square cockerel - a vivid splash of colour against municipal stone - without being amused. The Piccadilly Circus snow globe is another manifestation of a city sufficiently at ease with itself to have a great big joke.

This self-assurance, which the Olympics helped stimulate, used to be New York's defining characteristic, but I didn't get that sense this time around. London is now the restaurant capital of the world, our galleries and museums are second to none, and even our transport system is, in most respects, modern and efficient. There is creativity everywhere you look. Sometimes, it takes a trip away to make us appreciate what we have at home.