Trafalgar Square's empty Fourth Plinth -- whose neighbours include statues of imperial heroes such as Admiral Horatio Nelson and King George IV -- will be the base for "Powerless Structures, Fig. 101".

The 3.1 tonne bronze boy on a rocking horse adds a bit of subversive Scandinavian cheek from Danish and Norwegian artists Michael Elmgreen and Ingar Dragset to the otherwise regal plaza.

Built in 1841, Trafalgar Square's Fourth Plinth was meant to be occupied by another triumphant equestrian statue, but was left vacant due to a shortage of funds.

The new statue was unveiled on Thursday after winning a competition held by the Fourth Plinth Programme, charged by London Mayor Boris Johnson with selecting art to show on the vacant podium.

"It's a very clever twist on the equestrian statue which is what the plinth was originally built for, and instead of celebrating military victory, it celebrates innocence and childhood - I think Londoner's will love it," Munira Mirza, the Mayor's advisor on culture and youth told Reuters.

Since 1998, the programme has exhibited often controversial artwork on the podium including a ship-in-a-bottle and human statues.

"It's lovely that it can be here as a monument," 30-year-old French tourist Daniel said.

"I like how it's an idea of looking forward rather than looking backwards," said onlooker Sandra Reeves.

As London gears up for tourists arriving for the Olympic games, the director of the Fourth Plinth Programme Justine Simons said she hoped the boy and horse would be seen as fitting in with London's celebrated visual arts culture.

"London is really known as a capital of visual culture, it has the Tate Modern that is the most visited contemporary gallery on the planet...so it's absolutely right that we celebrate contemporary art in the modern city."

The statue will show on the Northwest Plinth of Trafalgar square for 18 months.

(Reporting By Ethan Bilby, editing by Paul Casciato)

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