Inside, rehearsal rooms are flooded with greenery and light. The concert space is surprisingly compact-surely uneconomic, I protested. Not at all, replies M. Hamard. It has 2,400 seats, hundreds more than the Salle Pleyel. The reason it feels small is that Nouvel stipulated a maximum 35-metre distance from top row to stage, an intimacy rare to orchestral concerts. The front rows can be removed to enlarge the stage space for mega-symphonies. The sound design is by Yasuhisa Toyota, the acoustician behind the impeccable sound of Los Angeles's Walt Disney Hall.

The new Philharmonie is a statement hall — a building which shouts from every angle, over and again, that Paris believes in its public and will take risks to please it, as London seldom does. The hall howls out our deficiencies. It is tantamount to the Mayor of London ordering the demolition of Brent Cross shopping mall and replacing it with a temple of music to serve the slumbrous north-west suburbs. Fantasy time.

And the cost? The Philharmonie was budgeted at €200 million — not much more than a South Bank refit — and is running some way over at €387 million. No one blinks an eye at the overrun. Successive presidents and mayors have gone on record to endorse the project with every semblance of faith and enthusiasm.

There you have it. English politicians are afraid and ashamed of providing for the arts — afraid of philistine MPs, media and voters and ashamed of their own ignorance and timidity. The French are proud of their patrimony and willing to invest in a vaguely imagined future. Half-English, half-French, I am torn internally between prudence and vision, always knowing which quality I much prefer. London needs a decent concert hall. Dammit, Boris, why can't we have one like Paris?