But they see clear advantages for girls to be taught on their own, even though they already outperform boys in language GCSEs, the study by a Manchester University teacher-trainer found.

Many of the 25 teachers interviewed said that they dreaded taking the all-boys class and resented the effort needed to teach them basic skills, according to Amanda Barton, a lecturer in education.

Setting by ability, reducing class sizes and matching staff to pupils of the same gender increased the success of single-sex classes, Dr Barton’s study of five mixd comprehensives found.

At one of the schools, 68 per cent of boys in a mixed-ability single-sex class achieved at least a GCSE C grade, compared to only 33 per cent in the mixed groups. Nearly 90 per cent of girls in the single-sex class achieved a good GCSE pass compared to only 48 per cent in the mixed classes.

Most of the 1,500 pupils polled were convinced that they worked harder in single-sex classes.

The findings of ‘Raising Boys’ Achievement in Modern Foreign Languages through Single-sex Grouping’ will be presented at the British Educational Research Association conference which will be held at the University of Cardiff on September 8.

More male teachers, 9