Anish Kapoor installed a giant sculpture in the Turbine Hall

In three short years the Tate Modern gallery has become part of the capital's cultural landscape and an essential stop for many tourists treading the art trail.

The opening of the gallery on London's South Bank looked to be a risky venture when it was unveiled in 2000, as questions were asked about the need for a gallery dedicated to modern art.

The project cost �134m, with �50m of lottery money going towards renovating the derelict Bankside power station, which of course raised opposition.

But its first year exceeded all expectations as more than five million visitors poured through the doors.

Perhaps unsurprisingly, the Tate Modern could not sustain such enthusiasm and visitor numbers did drop after the first year.

And there has been the inevitable struggle to balance the books, experienced by many arts institutions, as funding has been cut, forcing it to tighten its belt.

The gallery has been committed to offering free art wherever possible in keeping with the legacy of Henry Tate, who donated his art collection to the nation.

But it does charge for major exhibitions, which have included an Andy Warhol retrospective and one dedicated to surrealists.

The Warhol exhibition proved a success

The 2002 Warhol show was seen by more than 220,000 people during its two month run and received acres of press coverage.

The changing nature of the gallery's spacious Turbine Hall also ensures repeat visits from the most dedicated modern art enthusiasts.

Turner Prize winner Anish Kapoor created a giant indoor sculpture Marsyas, made from metal and PVC, which was a headline-grabber.

Despite a drop in visitor numbers, Tate Modern has reigned as the only major gallery offering contemporary art in the capital on a massive scale.

But after nearly three years it saw its first threat to its crown with the opening of the Saatchi Gallery, at nearby County Hall.

The Saatchi Gallery houses some of the names that brought modern art to the attention of the masses, sparking debate about the merit of the work produced by the movement.

Works by Tracey Emin, Damien Hirst and Marc Quinn are among the star attractions to be found in County Hall, the former home of London's city government.

But where the Tate has steered clear of art's bad boy Hirst, the Saatchi gallery is positively brimming with his creations.

The Gallery was built in a disused power station

Respected New York Times art critic Michael Kimmelman recently said Londoners had overtaken even New Yorkers in their "appetite for London art".

Having taken in a number of galleries in the capital, including the Titian exhibition at the National Gallery and the Saatchi Gallery, he was full of praise for the art scene.

But Mr Kimmelman warned that the new gallery had become a "stick with which to beat Tate Modern, whose glum industrial architecture is looking weary and causing former enthusiasts to rethink".

So if Tate Modern is to survive the competition it cannot afford to sit on its laurels and must build on its reputation as one of the world's greatest collections of modern art.

It must also evolve and vary the experience, so its visitors return time and time again.