THE full extent of the gap in performance between girls in single-sex and mixed schools has been detailed by official figures.

While 72.5% of pupils in girls-only independent schools won A grades in maths A-level last year, the figure was 64.9% for girls in their mixed equivalent. The overall national figure was nearly 30% lower.

The gap for English between girls at single-sex and mixed independent schools was even greater — 59.4% against 40.9%, according to the data released to the Girls' Schools Association by the Department for Children, Schools and Families.

Rebecca Ogilvie-Smith from Oxfordshire, who has just scored top grades in all her AS levels at Cheltenham Ladies College, Gloucestershire — while also winning top grades in her French A2 — said attending a single-sex school had taken off "a certain pressure" which the presence of boys can bring.

"There is a very intense feeling of community and it is not judgmental," said Ogilvie-Smith. "Your focus is not on how you look."

In recent decades, single sex schooling has declined in popularity, falling from nearly 2,500 30 years ago to about 400 now. In the past 10 years alone, some 120 independent schools have gone co-educational. Some of the best known former boys' schools, such as Wellington and Uppingham, are now coeducational although some of the best-known, including Eton and Winchester, have remained boys' only.

Leading girls' schools have been far more likely to resist going fully mixed. Vicky Tuck, principal of Cheltenham and president of the GSA, said the new analysis — a full breakdown for last week's national A-level results is not yet available — showed the value of girls-only schooling.

Overall, girls in single-sex schools outperformed in 19 subjects and lagged mixed-school girls in just four.

"Parents want their girls to be first citizens," said Tuck. "The school exists for the girls, it gives them confidence, opportunity and a sense of potential."

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