London: A school has become the first to ban skirts for girls aged nine as youngsters tried to copy risque pop stars such as Rihanna by raising their hemlines.

The middle school, for children aged nine to 13, is bringing in a trousers-only rule from September.

It is also introducing a blouse ban next year, after which girls will be required to wear shirts like their male classmates.

The ban comes as increasing numbers of young girls copy the “sexy schoolgirl” look popularised by celebrities such as Rihanna and Katy Perry. Pupils of TV’s fictitious Waterloo Road school are also often seen in short skirts.

David Doubtfire, headmaster of Walkwood Church of England Middle School in Redditch, Worcestershire, said the ban would eliminate “unladylike” short skirts.

He added: “Some of the older girls were beginning to wear extremely short skirts. It was becoming difficult, especially when it came to them sitting down in the hall. It was very unladylike. We would ask them to make their skirts longer, but they would just roll them up again when we turned away.

“Parents seem to be all right about it, although 20 have written to us to say they are not happy.”

But one parent, who did not wish to be named, said the ban was “crazy”. The mum-of-one added: “You hear about the over-sexualisation of children but to call a nine-year-old girl unladylike is absurd.

“They aren’t ladies, they are young girls. And to stop them wearing skirts is going to confuse them.”

The campaign group School Skirt Ban has asked the Equality and Human Rights Commission over whether skirt bans are legal.

A spokesman for the group said: “We were told that the Commission would strongly advise schools against doing this because such an action would be considered a case of indirect discrimination.”

He said skirt bans exist in 63 secondary schools, but none had been imposed on nine-year-olds before.