The four bronze lions of London's central Trafalgar Square got a temporary addition on 28 January, with a clockwork sculpture of the animal unveiled to highlight the plight of big cats. The statue, made of clockwork mechanics, will stand in the square for just a day before being auctioned off to raise money for National Geographic's Big Cats Initiative, which says it aims to halt the decline of big cats in the wild. According to the initiative, recent estimates indicate there are likely some 30,000 African lions in the wild.

"I think most people don't believe actually lions are in danger, I think they think there's a lot of them about," said Jeff Ford, managing director of television channel Nat Geo Wild. "But just last month they were put on the endangered species list and even other cats are now under 10,000 animals in the wild."

Among the issues affecting big cats are poaching and loss of both prey and habitat. The killing last July of Cecil, Zimbabwe's most prized lion, by an American big-game hunter, sparked a global controversy and set off a backlash against the African hunting industry.

"There are actually more lion statues in the world than there are lions roaming in the wild," British television presenter Rachel Riley, who unveiled the sculpture, said. "So to try and highlight the issue and say that there are things that we can do, this is being unveiled here for one day only."

One book, published in 2012, gives an idea of how many lion statues there are just in London: London Pride: The 10,000 Lions of London. Sculptor Iain Prendergast, whose works have appeared on television show Game of Thrones as well as in artist Banksy's Dismaland theme park, described the statue.

"On the body, mainly as if it was the inner workings of a clock, so it was cogs, levers and coils and all sorts of things like that," he said at his workshop. "And then up to, obviously the eyes, we've got clocks in them, clock faces but yeah, it's just looking at each little part of the clock, obviously the hands for the mane, just seeing whatever sort of links in with the actual physical resemblance of the cat."

The unveiling was held ahead of Nat Geo Wild's Big Cat Week, running from 1-7 February, during which the channel will show programmes about the animals' plight.