Advice for those organising pupils’ work experience: don’t send them to beauty parlours that turn out to be brothels.

That was the error made by a school in Osijek in eastern Croatia. A group of its teenage girls started work at the De Luxe beauty salon, where they soon noticed male punters heading for the back room.

Police arrested the owner, Jasmina Hajric, 35. Her 34-year-old partner Aleksandar Djuranovic was also arrested after he was found with a gun and marijuana.

A police spokesman said: “The girls’ suspicions were aroused when they saw almost all the customers were men ... They said they knew what was going on when the owner demanded they take home dirty bed sheets and wash them.”

Danica Carnohorski, head of Rudjer Boskovic Osijek School, said: “The girls came to us and we sent one of our teachers around and they noticed something odd was happening there. We refused to send the girls back there and called the police straight away.”

British teachers piloting the 14-19 hair and beauty diploma should take note.