A spiralling 400-foot sculpture designed by Anish Kapoor

A spiralling 400-foot sculpture designed by the Turner prize-winning artist Anish Kapoor is set to win the competition for a monument to mark the 2012 Olympic Games.

Boris Johnson, the mayor of London, is planning the pounds 15 million artwork, which he hopes could become a popular tourist attraction.

The sculpture, to be built in the Olympic park, is to be funded by steel baron Lakshmi Mittal, Britain's richest man.

Although the exact design is being kept secret, the asymmetric steel structure is understood to resemble a cluster of interlocking fractured rings.

The form is intended to complement the sweeping curves of the nearby Aquatics centre, by Zaha Hadid, and its form nods to the five rings of the Olympic logo.

It is two-thirds the height of the Gherkin skyscraper in London; six times taller than the Angel of the North; and twice as high as Mark Wallinger's pounds 2 million white horse.

The sculpture will incorporate lifts for visitors and offer sweeping views over London. A restaurant is also planned, though its inclusion will depend on the ability of Cecil Balmond, the project's engineer, to overcome significant structural challenges.

Like the Skylon, the futuristic sculpture-cum-Zeppelin built for the 1951 Festival of Britain to wow a war-weary nation, it is hoped the artwork will become a symbol of optimism as Britain emerges from recession.
Securing funding for the project is a coup for Johnson, who has been urging London's super-rich to give something back to society.

A source close to Mittal said he decided to fund the project as a "gift to the city he loves", after Johnson suggested the idea last year.

Although a winner has yet to be announced, it is understood Kapoor's design has pipped a rival entry by Antony Gormley, famous for his iron figures.

"It's an extremely exuberant design," said Barbara Gladstone, Kapoor's art dealer in New York. "I think it's an incredibly appropriate work for this period because it uses all the latest technology.

"If you think of the Eiffel Tower in 1889, that was something that could never have been built before. Look at what it meant in the end - that kind of symbolism is what's here, in this work. It's a statement of optimism and all that's good about being alive today."

Kapoor has earned a reputation as the "Mr Big" of modern art, producing sculptures that dwarf the viewer. One new work being assembled in Teesside, called Temenos, resembles a huge pair of tights stretched between two rings, hovering eerily over the post-industrial landscape.

His Olympic artwork will be the tallest in Europe, beating a 315ft statue of Peter the Great in Moscow, built to celebrate the 300th anniversary of the Russian navy in 1998.

The Olympic sculpture would be lit at night and is expected to draw tourists to East London after 2012. Its steel frame reflects Mittal's business, which has earned his family a pounds 10.8 billion fortune.

Spokesmen for Johnson and Mittal refused to comment on the scheme. A winning design is expected to be revealed in six weeks' time.