Conservation experts have been unable to remove graffiti spray painted on Arbroath Abbey – leading to fears that the damage may never be repaired.
It comes after the 12th Century monument was targeted in a two-day vandalism spree in July.
Yobs spray-painted the walls and path, climbed scaffolding to smash a window, set off fire extinguishers and removde chairs.
A team from Historic Environment Scotland, which is responsible for the upkeep of the landmark, have made two attempts at coming up with a method to remove the graffiti.
However, they say the porous nature of the stone means they have been unable to find a safe way to wipe the lettering away.
Harry Simpson, chairman of Arbroath 2020, which is organising a number of events to celebrate the 700th anniversary of the signing of the Declaration of Arbroath in 2020 said: “I was sick to the stomach when I first heard about this vandalism.
“I am saddened and disappointed that it cannot be fully removed at the moment, but I remain hopeful that advances in technology will allow it to cleaned off in the future.
“I just don’t think there is enough punishment for people who do this kind of thing.
“It’s bad enough when it happens on ordinary property, but it’s so much worse when somewhere so important as the abbey is vandalised.”
The stonework was tagged with the initials “AYT”, believed to stand for “Arbroath Young Team”, using industrial spray paint thought to have been stolen from a nearby building site.
A spokesperson for Historic Environment Scotland said teams had done everything in their power to tackle the damage.
“To remove graffiti of this type, we follow best practice as set out in our Technical Advice Notice,” the spokersperson added.
“It is first assessed to determine the graffiti type and the cultural significance and condition of the material to which it has been applied, such as plaster, stone and timber for example.
“Various trial removal techniques are then undertaken to determine the least disruptive removal method.
“Once the methodology of removal has been agreed, our Monument Conservation Unit then undertake the painstaking work to remove the graffiti.
“In this instance, two applications of the removal process have been undertaken, however the porous nature of the stone, which has absorbed some of the paint, has prevented complete removal at this stage.
The vandalism spree caused widespread anger in the town at the time, with council leader David Fairweather describing the perpetrators as “mindless buffoons”.
Youths were also seen jumping from the scaffolding onto the roof of a nearby house.
A spokesperson for Police Scotland said: “Three boys aged 16, 14 and 13 have been reported to the Children’s Reporter.”