I have little left of my day in London. I hurry past the Black Friar pub and find the north end the pedestrian-only Millennium bridge. It is busy. Like everyone else, I am determined to get to the Tate Modern that beckons from the south side of the river. I want to see The Clock.

In the middle of the bridge there’s guy lying down next to an open tool box. His clothes are daubed with paint of every colour. I say hello. He’s very friendly. I ask his name. “Ben Wilson.” He replies with a broad smile. “But people call me ‘chewing gum man’!”

Ben is relaxed and chats to anyone who stops. He’s not obviously chewing gum. I ask him what he’s doing. It’s clear he’s been asked this a thousand times. “I’m painting the chewing gum!” I gawp. I look down around my feet and along the shiny aluminium walking surface. I see there are thousands of stuck-hard pieces of discarded chewing. The penny drops. Ben’s canvas is the chewing gum! “It’s a great day for painting.” he says. “It rained last night so the gum’s clean!”

Using acrylic and enamel paints he has created hundreds of beautiful little fantasy designs scattered along the full span of the bridge. They include humanoid, animaloid and all sorts of -oids. Each is unique and intriguing. Some bear the names of visitors. I crouch to take photos. People trip over me; Tate-goers are too polite to curse me. Ben cheers me on.

Ben is an exhibited painter and sculptor. This work, for which he is apparently well-known in London, was inspired by his distaste for any kind of rubbish on the streets. It is a truly imaginative initiative. However, he has generated controversy. Is this vandalism? He was once dragged down to the local police station for painting public property. Clever lawyers argued that he is not defacing private property but merely painting rubbish and therefore is breaking no law.

Ben’s project requires an extraordinary dedication. It is as original and unexpected as it is opportunistic. I am totally uplifted. This has made my day. I skip down the steps to the Tate Modern where, I’m sure, the surface of the bridge will one day be exhibited.

Take a look at more of Bens work.