Teenage criminals enjoyed an orgy at a detention centre - after warders accidentally left dormitory doors unlocked.

This allowed the boys to sneak into the girls' room and take part in a Valentine's Day romp, it has emerged.

Now parents of the juvenile delinquents are calling for an inquiry into how staff could have been quite so lax.

The mother of a 15-year-old boy serving three months in detention said: "He told me they had all had sex in the one room - it was a big Valentine's Day sex romp.

"The staff on duty that night left the doors open.

"I was furious. No parents have been contacted about this - it had all been kept very hush-hugh.

"One father of a girl involved said he was going to sue the pants off them."

Centre manager Peter Curwen-Walker confirmed there were allegations of "an incident involving consensual sexual intercourse".

He said police had spoken to two inmates, though other reports have claimed up to six had taken part.