The largest UK exhibition of graffiti art ever held has been slammed by campaigners who say it "legitimises" street crime.
The artwork has been created for the exhibition
Keep Britain Tidy (KBT) criticised Manchester's Urbis museum after a survey showed councils are paying out millions of pounds to remove graffiti.
Sue Nelson, of KBT, said "what Urbis should be doing is condemning graffiti...that blights our most needy" areas.
Urbis said however, it is not encouraging vandalism with the works.
Ten of the world's best-known street artists are exhibiting their work at Urbis in the "Ill Communication" exhibition, which runs until October.
Ms Nelson, assistant chief executive of KBT, also criticised Manchester City Council for not questioning its sponsorship of Urbis after carrying out an anti-graffiti campaign earlier this year.
"Council tax payers in Manchester are in the bizarre position of helping to fund a museum which exhibits graffiti, while at the same time forking out thousands of pounds to have these problems removed from the streets of their city," said Ms Nelson.
But Scott Burnham, creative director at Urbis, said KBT should have come and viewed the exhibition first before making their comments.
"They made their comments before this exhibition opened," he said. "The very reason Urbis is doing it is that we're providing the public with an opportunity to view what is happening in street art in major cities around the world.
"We're inviting people to come in and form their own opinions."
He said the works do not compare to a "piece of scrawl on the side of a building made with a magic marker", and the exhibition will not encourage people to start creating illegal graffiti.
"It will influence people in the same way a visit to the Tate would - it's not encouraging people to walk out and start spraying the sides of buildings, but to go home and start working in their own sketchbook," he added.