"IT WAS like something out of a horror movie."

Those were the words of one petrified parent after she saw teenagers with scarves covering their faces intent on causing chaos at a disco at Thornwell Primary School, in Chepstow.

The scarf-wearing youngsters illegally entered Thornwell Primary School grounds during the once- monthly disco and began hammering on the windows.

"It was a terrifying sight. I've seen the film Scream and it was as scary as that," said the parent of a nine-year-old boy who was at the disco. The mother, who wishes to not be named, continued: "All the parents were scared for the safety of the children so the police were called. It looked to us like the yobs were all girls, aged about 15, and there were about five of them."

Thornwell Primary PTA chairwoman Pauline Thomas, who organised the disco, said: "There was no problem actually inside the disco itself, but there were about five girls and boys who came on to the school and caused a bit of trouble.

"They wore scarves over their faces and it made them look very disturbing. "Somebody called the police and they quickly came and did a sweep of the area."

"It was another highly successful disco where we raised more than £200, but it is a shame it was disturbed by these youngsters trespassing on the school grounds.

The money raised by the disco goes towards further entertainment events for the children, because the school only has a limited budget. They have become a regular event and are greatly looked forward to by the children.

Bob Young, the headteacher of Thornwell Primary school, said: "The trespassers came on to the infant yard and caused a lot of mischief, from what I have heard.

"Unfortunately, we do seem to have problems with trespassers coming on to the school property and it is something we are trying to tackle. "Fortunately, the teen-agers fled before the police came.

"We are always grateful for the help the police give us and I know that the discos are important to the children of the school."

A police spokesperson said: "We received a call from Thornwell Primary School on March 31, after a complaint of youngsters trespassing and then banging on the windows of the school.

"When officers arrived at the scene the perpetrators had fled."