A coronavirus mural painted by world-famous street artist Banksy has been cleaned off a London Underground train, apparently by cleaners who did not understand its significance.
The cleaners did not know who had painted the pro-mask message on the inside of a London Tube train and treated it like any other graffiti, the BBC reported.
Banksy uploaded a video titled If You Don't Mask – You Don't Get on to his Instagram page on Tuesday.
It shows the reclusive artist wearing protective gear and spray-painting pictures of rats sneezing on the inside of the train to illustrate how not wearing a mask helps to spread Covid-19.
It was not immediately clear how long the work was actually on the train.
Joey Syer, from MyArtbroker.com, said the mural could have been worth about £7.5 million (Dh34.6m/$9.4m).
Some people have criticised the cleaners and Tube operator Transport for London for removing the painting, while others praised them for diligently doing their job.
Others suggested the mural was an act of publicity and that Banksy knew the work would not be in place for long.
"It was treated like any other graffiti on the network," a transport authority source said.
"The job of the cleaners is to make sure the network is clean, especially given the current climate.
"We'd like to offer Banksy the chance to do a new version of his message for our customers in a suitable location."
The pro-mask message is in line with official advice that travellers on London public transport should wear masks.
The work includes rats, in Banksy’s usual style.
One image features a rat holding a bottle of antibacterial hand wash, while another shows a rat using a face mask as a parachute.
The video closes with the words, "I get lockdown" painted on to the wall of an Underground station, followed by "but I get up again" sprayed on the inside of a train door.
There have been almost 292,000 confirmed cases of Covid-19 in the UK and more than 45,000 deaths.
The country is emerging from national lockdown orders and trying to reopen its economy.
Last month, Banksy shared a new piece of art on his Instagram page, inspired by the death of George Floyd and the Black Lives Matter protests.
Scroll through more of Banksy's work in the gallery below: