A small but determined group of volunteers set to work with mops and buckets in one of the seven subways at the Elephant & Castle on Saturday afternoon.
The grime-busting event was led by Richard Reynolds, co-founder of the Save our Subways campaign.
Best known for his guerrilla gardening exploits around SE1 and beyond, Reynolds has turned his attention to the fate of the pedestrian underpasses at Elephant & Castle.
The Save our Subways campaigners are calling for the tunnels to be retained when the gyratory system is remodelled as part of the Elephant & Castle regeneration.
The campaign's recommendations for improving the subways include better wayfinding signs, brighter lighting, new and repaired artwork and pop-up performances by street entertainers.