A cleaner was subjected to a terrifying ordeal after a gang of up to 20 vandals clambered on the roof of a school and hurled furniture about at dusk as she was trying to leave.

The woman was trapped in Ysgol Pen Barras until the police arrived and the vandals fled

The chair of governors at the Ruthin school, Councillor Huw Hilditch-Roberts says the woman was terrified and says the area is now under regular surveillance.

The group of youths left litter behind at the Rhos Street school while also damaging outside furniture and play equipment.

Cllr Hilditch-Roberts said: “During the holidays one of the cleaners was inside the building, and these youths were on the roof terrifying her

“It was getting dark and she wasn’t able to leave until the police had come

“They’ve trashed furniture and play areas. Children shouldn’t be put at risk of finding alcohol or glass dumped on the ground. The litter and debris that could be picked up the next day is was everywhere.

“We are aware who they are but the police are working with us to catch them, and we will be on the look out.

“The area is surveilled regularly as the protection and wellbeing of our staff is paramount. As a community we will not tolerate this sort of behaviour.

“They’re endangering themselves as well as others.

“It’s a when there’s been so much good out of the school recently.”

According to the school’s head, Marc Lloyd-Jones parts, of the school’s outside play area have suffered extensive damage.

The felt has been ripped from the roof of a shed with the roof partially caved in.

Furniture has been thrown around with cans, broken bottles and cigarette ends strewn across the floor.

Mr Lloyd-Jones said: “It’s general mindless violence, throwing around outside furniture, smashing up the Wendy house, cigarette butts and cans thrown about.

“They’ve been intimidating to the cleaners, with gangs of 20 up there making a nuisance and destroying things.

“The caretaker’s been trying to tidy up after them all, and as the summer nights lengthen they gather for their alcohol and drugs or whatever on the school.

It’s just a mess. They throw tables around, that type of thing, beer cans, bottles, broken glass, it’s a danger for our kids when they come back.

“We’ve had parents contact police when they’ve seen them running on the roof. There could be a really nasty accident as well, the roof isn’t in the best state of repair anyway, it could be really dangerous for them.”