What are the advantages of going to an all-girls school?

"Surely", he said, "in this day and age it’s obvious that girls should be educated alongside boys."

His question and his subsequent comments made it clear that in some people’s minds, the girls’ school is an anachronism equated most often with either St Trinian’s or Enid Blyton’s Mallory Towers.

In fact, statistics show that all-girls’ schools have grown in popularity over the past ten years.

There are more girls educated in girls’ schools than boys in boys’ schools, and most co-ed schools have more boys than girls in each year group.

There is also a huge amount of evidence that indicates that when girls are educated in co-ed environments, they underperform and undercontribute compared to the boys, which is in contrast to how they perform and achieve in single-sex environments.

Lindsay Hughes says that evidence shows girls perform better in a same sex school (Image: Channing School)

Research data shows that if girls are working alongside high-achieving boys in the classroom, they’re likely to adjust their own educational goals downwards so that they don’t stand out in front of the boys – but if they are in classrooms with high-achieving girls, they’re more likely to be true to their own goals and be more ambitious.

Indeed, the Department for Education’s own results data shows that girls in girls’ schools outperform their co-ed peers at both GCSE and A-level.

We also know that the percentage of girls selecting A-level sciences and maths is much higher in single-sex schools than it is in co-ed schools. However, many parents won’t be aware of data that shows that in a co-ed class even the best teachers end up interacting more with the boys: between 10% and 30% more attention is paid to boys than girls in a co-ed classroom, particularly in science and maths.

As I tell prospective parents when they visit Channing, in an all-girls’ school everything is designed for girls.

We’re experts in looking after and supporting them, they are listened to and they take all the leading roles right the way through the school. This means they leave school and go out into the world expecting to be heard and feeling as though they have every right to become leaders.

At Channing - and indeed, in all girls’ schools - we enable our pupils to be brave, to have a go at things, even when they fear they might fail or not win.

It is vital that our girls grow into young women in an environment where they are free from stereotypes, able to build resilience and take their next steps beyond school, able to take all that life can throw at them.

• Mrs Lindsey Hughes is headmistress of Channing School in Highgate.