The latest artwork to adorn the fourth plinth in Trafalgar Square – a four metre-high bronze sculpture of a boy riding a rocking horse – was unveiled by actress Joanna Lumley.

Ms Lumley said she was “thrilled” to be asked to unveil the “completely un-threatening and adorable creature” in central London.

The golden-coloured sculpture, called Powerless Structures, Fig.101, is designed by Scandinavian art duo Elmgreen and Dragset.

The pair released a statement saying it was “up to the public to love or hate it” and added it was “a huge honour” to show their work in the square.

Ms Lumley said she first met the duo four years ago when she was asked to provide the voice for one of their sculptures, adding: “So I was especially pleased that today I’ve been brought back here for a statue that I think will speak for itself, it doesn’t need any prompting from a human.”

She said the work, which replaces Yinka Shonibare’s large-scale Nelson’s Ship In A Bottle, would make “us all look around our fantastic city and look at all the other sculptures and statues which adorn this miracle of a place which is called London”.

Ms Lumley described the work as a “golden boy which I hope bodes well for the future for the Olympics”.

The plinth, in the northwest corner of the square was originally intended to hold a bronze equestrian statue of King William IV but it was never installed.

Other notable artworks which have featured on the empty plinth have included Antony Gormley’s One and Other, which saw 2,400 people taking the space for an hour to do what they wanted, with some standing naked.