An Antony Gormley sculpture in Edinburgh has had its modesty preserved after a mystery passerby on the Water of Leith dressed the naked figure in underpants with “bawbags” written across them.

The sculpture is part of the artwork 6 Times, which comprises six life-size figures – casts of the Turner prize winning artist’s body.

Located between the grounds of the Scottish National Gallery of Modern Art and the sea at Leith Docks in the Scottish capital, the artworks were originally installed in 2010.

Some of the sculptures were removed following issues with the tilting mechanisms in 2012. They were fully reinstalled in May.

“It was a privilege to make these works for Edinburgh and now they are coming back to stay – I’m delighted,” Gormley said last month.

Simon Groom, the director of modern and contemporary art at the National Galleries of Scotland, said at the time that they were thrilled to be reinstalling the artwork.

“We are extremely grateful to Antony, his studio, Edinburgh city council and everyone else who has played such an active part in ensuring the success of the project,” he said.

“This is a meditative and reflective work, which brings art out into the wider community along Edinburgh’s beautiful Water of Leith.”

Locals and visitors have reportedly mistaken the cast-iron pieces for imperilled walkers, and police and ambulance services were notified of their reintroduction.

It is believed that the pants were put on the sculpture as a practical joke. It is not the first time a Gormley sculpture has been dressed up in such fashion.

On Christmas Eve last year, a group of pranksters scaled the Angel of the North outside Gateshead and placed a giant Santa hat on its head.

Days later, a member of the group dressed as the Grinch removed the headwear.