A public art project in Wales has gone to the… sheep?

As part of an outdoor, ambulatory performance art project staged by the National Theatre of Wales, The Gathering/Yr Helfa, a 100-foot mural was painted onto the slope of Snowdon, the tallest mountain in Wales. The mural, which features the text of a poem by the national poet of Wales Gillian Clarke, was painted near the popular climbing spot known as Gladstone Rock with the permission of the National Trust, to whom the land belongs.

Though it was intended to be washed away by the rain, the exceptionally hot late summer sun (the performance ran September 12–14) has apparently “cooked on” the text, as one climber put it to the Independent, and now the artwork has been deemed a nuisance tantamount to graffiti.

“We are genuinely sorry that it is taking this long, but it is our priority to put things right as soon as possible,” the theater company said in an apology. The massive poem was one of the most dramatic features of the four-hour experimental theater piece, which was developed over the course of four years and was conceived as a rumination on the work cycles of the local sheep farmers.

“We have sympathies for the artistic endeavors involved, but what is left is no more than graffiti in a semi-wild landscape in a national park,” Elfyn Jones, the British Mountaineering Council’s officer for Wales, told the Independent. “It’s unfortunate to say the least.”