The latest artwork by enigmatic British street artist Banksy was attacked by a “drunk halfwit” who attempted to damage the powerful mural painted on a suburban garage wall in south Wales.

A security guard, who is paid for in part by Hollywood actor Michael Sheen to protect the artwork in his hometown, chased the culprit off and called police before it was destroyed.

The artwork has also been covered with a protective plastic screen, which Sheen also helped contribute towards. It was fitted for free by a local businessman.

“Some drunk halfwit has tried to pull the fencing down and the protection glazing at the Banksy artwork tonight,” Gary Owen posted on the local Facebook page he runs called Neath Port Talbot Life.

“The security guard chased him off and police were called. This art is for Port Talbot, Neath and surrounding areas. We do not want it wrecked.”

Mr Owen, 55, said he messaged the artist in August, asking him to highlight Port Talbot’s dust problem.

The mural then appeared on Tuesday, with Banksy claiming responsibility on his website and Instagram account on Wednesday, causing quite a stir in the south Wales steel town.

Residents, who have been complaining about a thick layer of black dust they believe is coming from the town’s steelworks, believe the mural is a powerful social statement.

The work, in the shadow of the town’s dominant steelworks, shows a child seemingly playing in the snow, standing by a sled with his tongue out, tasting the falling snowflakes.

But round the corner of the garage, it shows smoke rising from a burning fire, and the snowflakes are actually falling ash.

“It’s lovely because it brings over a number of messages,” said local resident Kirstin Tucker.

“When you first look at it from this angle it just looks like there’s a little child out there in the snow playing,” she told AFP.

“But when you see the flames and the pollution that comes around from the other side of the picture, it brings out the thoughts of what Port Talbot was all about, the industrial side of things and the history.”

The garage is owned by Ivan Lewis, 55, a steelworker at the town’s Tata Steel plant.

“It started off as fun, but now it’s gone to stress. It’s down to not sleeping, but now I’ve got the security there it’s taken that weight off me,” he said.

“I’ve never experienced anything like this. My phone is ringing, on my house phone there’s 1,000 messages on it.”

The father-of-one said he has not decided what to do with the artwork, and denied receiving any offers to sell it.

“I’m really just rolling with it at the moment and I don’t know where it’s going.”

The work is Banksy’s first in Wales.