A protective layer will be put over a new Banksy artwork which appeared on a disused Hull bridge but was quickly defaced.
The picture of a young boy in the familiar Bansky stencilled style along with the slogan "Draw The Raised Bridge" appeared on the Scott Street Bridge over the River Hull last week.
But the picture was defaced over the weekend when someone appeared to have covered it with white paint, which was later cleaned off by local window cleaner Jason Fanthorpe.
On Monday, Hull City Council said it will be protecting the picture.
In a statement, the authority said: "To prevent further damage staff will be on the site of the Scott Street Bridge this morning applying a protective layer to the Banksy artwork.
"This temporary measure will help to ensure that the public can continue to enjoy the work and prevent, where possible, further damage."
Mr Fanthorpe told BBC Radio Humberside how he used water and white spirit to restore the image.
He said: "Banksy, love him or hate him, has international prestige and he'd gifted the city with his art. I could not just sit back and not try to help.
"Being a window cleaner I had the equipment at hand, I knew we'd need ladders as I'd been to see it earlier in the week."
The work was first spotted on Thursday and crowds gathered over the next few days to look at the picture on the roadway of the structure, which a bascule bridge now in a permanently raised position.
Banksy later confirmed his authorship on his Instagram.