Even if you are Banksy, tagging is forbidden on London's Underground.

Transport for London, the transportation agency for the greater London area, scrubbed the acclaimed street artist's latest work on the subject of COVID-19 from one of its trains, erasing a visual warning on the dangers of skipping face coverings.

Banksy uploaded a a 59-second video to his Instagram and YouTube pages on Tuesday that showed him spray painting on a Circle Line train.

Clad in a white boiler suit, mask, goggles, and an orange jacket with the words "stay safe" on the back, he climbed on the train under the guise of being a maintenance worker.

He then stenciled his trademark rats in discreet corners of a train car. One memorable image shows a sickly rat with a runny nose that sneezes and spreads a spray of droplets across a window.

Transport for London officials say the works were removed because of a strict anti-graffiti policy. But they are hoping Banksy might be persuaded to tag again.

"We'd like to offer Banksy the chance to do a new version of his message for our customers in a suitable location," the agency said in a statement.