A Thomas Gainsborough painting known as The Morning Walk (1785) was damaged Saturday afternoon at the National Gallery in London after a man scratched the work with a screwdriver.

Keith Gregory, 63, of no fixed address, was charged with causing criminal damage and has been remanded to appear at Westminster magistrates court today, Monday, March 20.

The east wing of the gallery, which is home to British painting, was evacuated for two hours following the incident, and the painting was taken down from display.

“The damage is limited to two long scratches which have penetrated the paint layers, but not the supporting canvas,” a spokeswoman said in a statement. “The painting was removed from display and examined by the gallery’s conservators, who are now assessing next steps.”

Mr and Mrs William Hallett (‘The Morning Walk’) shows a couple, who are engaged to be married, on a stroll through the countryside with a dog at the woman’s heel. Portraits of this kind were a popular status symbol at the time.

Mark Bills, director of Gainsborough’s House, the museum in the artist’s former home in Sudbury, Suffolk, spoke to the Guardian, saying the painting is “one of [Gainsborough’s] great masterpieces: he was absolutely at the height of his powers … When we think about Gainsborough, it’s usually from around these years. When you think of the elegant portraits of the Georgian period, that’s the one that comes to mind.”

“It’s amazing what conservators can do,” he continued. “You probably won’t see a difference … I’m relieved from what I’ve read it hasn’t caused any permanent damage.”