GIRLS from St Anne's Convent School in Southampton sharpened their code-breaking skills by taking part in an online adventure game, run by Southampton University.

They took part in the National Cipher Challenge, which has already had 3,500 hits since it was launched two months ago.

The aim is for youngsters to use their mathematical skills to become code-breakers by solving a succession of mysteries in an adventure story set during the Second World War.

Juliet Offner, a maths teacher at St Anne's, which has 960 pupils on roll aged from 11 to 18, said: "The students find the Cipher Challenge very exciting.

"We always have an eager group on Thursday evenings waiting for the new instalment.

"The ingenuity required to break codes is fascinating. "In undertaking the challenge we have acquired many new mathematical and ICT skills and are beginning to learn to program computers too."