But what to wear? Most people had sensibly concluded that Islington was more matt black than black tie, and the stalls and circle were expensively upholstered with Savile Row and Armani. There were a few ballgowns but these looked more out of place than denim in a theatre that didn't even bother with the traditional national anthem. Photographers combed the excited throng in the foyer in search of famous faces, which included those of Cherie and Tony Blair, Chris Smith, Trevor Phillips, Richard E Grant, Janet Suzman and Wayne Sleep. The house reeked of rich sponsors and massive goodwill. They were ready and willing to have a very good time indeed.
The entertainment was provided by Rambert Dance Company. Rambert are a splendid troupe with a loyal following, but most of the gala audience was really there to see the theatre and kiss air, and the artistic director Christopher Bruce would have done well to remember that. Instead of pulling out all the stops with a crowd-pleasing programme, he presented an over- long quadruple bill that was very much business as usual. There were two works from Jiri Kylian, artistic director of Netherlands Dans Theater, one from the distinguished American choreographer Paul Taylor, and a fine new piece from Bruce himself. It was a class act and superbly danced, but it was not the stuff to give this lot. The result was perversely low- key and although the audience received the excellent dancers with hearty politeness, there was none of the enthusiasm they would have shown for a more cannily chosen programme.
And it is not as if Rambert does not have blockbusters in its repertoire - Bruce may be weary of pleasing crowds with his exhilarating Rolling Stones piece, Rooster, but it would have made a better calling-card for Rambert and for modern dance in general.
The new Wells certainly deserved a show that pulled out all the stops and showed off the potential of this fine purpose-built dance house. The wide, handsome stage is truly magnificent and although the auditorium itself is not a thing of beauty, the sightlines are excellent and it will provide a discreet and flexible setting for any number of presentation styles. And the intervals aren't bad, either. Old Wells-goers, inured to the smelly squeeze of the old bar and foyer, could hardly believe the airy generosity of the public spaces. As the double-decker buses whizzed by outside, passengers turned to gaze in wonder at the gilded folk behind the vast new wall of glass. A great occasion. It is a pity that Rambert didn't quite rise to it.
A version of this review appeared in later editions of yesterday's paper. Rambert's bill of `August Pace', `Axioma 7' and `Embarque' runs at Sadler's Wells (0171-863 8000) until 17 October