Kevin Hawkins, head of modern languages at an independent school, admitted common assault and was sentenced to six months imprisonment, with three months suspended, at the South Gloucestershire magistrates court in Stroud.

The boy, whose name is not being disclosed, had been invited to Mr Hawkins's home for help with Spanish homework. Here the pupil was forced to take part in a series of forfeits for mistakes, including walking barefoot on drawing pins, stripping to the waist and lying on drawing pins and finally having Mr Hawkins place ice cubes on his bare chest.

The magistrates' chairman, Yvonne Cant, described it as an "unprovoked assault" carried out by someone in a position of "'trust and authority", and that the offence was so serious it justified a custodial sentence.

Magistrates heard from the prosecutor that the teacher had tested the boy on Spanish verbs and had made him perform a forfeit each time he made a mistake.

This began with standing on one leg and progressed to press-ups, before the boy was made to walk on drawing pins on the floor and then lie on top of them.

The schoolboy reported the incident to the school and to the police and Mr Hawkins subsequently resigned.