'It has changed the face of gallery visiting'

Hurrah. At long last London has a fully fledged museum of modern art. And not an exclusive, high-brow gallery that frightens away or bores the general public, but one that is a grand spectacle in itself and which has proved a colossal attraction for overseas tourists and natives alike.

Nicholas Serota should be loudly applauded for his vision and achievement in transforming a great building into a space that draws people from all over the world. Londoners are proud of this new addition to their landscape, proud of a monument that looks to the present and the future as well as to the past, and which will continue to be a major force in the contemporary art world. They are also proud that anyone may join in the debate: that the museum is free.

Sure there are defects - both in the permanent collection (extremely weak compared to those of the museums of modern art in New York or Paris), in its display and in the way the space of its extraordinary building has been deployed. But the essential thing is that it is there. In the next few decades the collection can be built up, and displays and exhibitions rethought; there would be little chance of this happening if the Tate had remained intact at Millbank.

In other words Tate Modern is a beacon, providing a focus for the contemporary art world that was missing. While London has long been the centre of the international art trade, and Brit Art has increasingly made its mark internationally, the lack of a museum dedicated to art of the 20th - and now 21st century - has been a disappointment.

Visitors are responding both to the building and to the art housed in it. The fact that both cannot be fully experienced in one visit is just one reason for return visits. (The amount of walking involved if you want to look at the art rather than the building is also astonishing, but part of the experience.)

The scale of Tate Modern's success means that of those lured, moth-like, through its portals, hundreds of thousands who would not otherwise have sought out modern art have experienced it. If even a small proportion of these look at and seriously consider the art, then Tate Modern has been a democratising force. It has thus achieved far greater access - New Labour's great museum mantra - than any number of programmes specially contrived for that purpose. It has proved that aiming high rather than dumbing down creates popular success. By introducing large numbers of willing visitors to modern art - and encouraging the habit, as a cool place to hang out in - it has quite probably changed the face of gallery visiting for ever.