A school concerned about rising hemlines has become the latest to ban girls from wearing skirts.
Northgate High School in Ipswich has removed skirts from its approved uniform list to stop students coming to lessons in "inappropriate attire".
It is the third school in the town to introduce such a ban.
When nearby Kesgrave High School introduced a similar ban it provoked a mixed reaction.
Some parents complained it restricted freedom of choice while others welcomed it as a way of maintaining standards.
It comes after Tewkesbury School in Gloucestershire put forward a similar proposal in April after its headteacher said some wore skirts which were "almost like belts".
Northgate headteacher David Hutton said that in recent years the ever-rising hemlines of some girls had led to staff sending students home to change.
Headteacher David Hutton said: "At Northgate we expect pupils to be well behaved, to work hard and comply with our rules and expectations.
"In return they receive a good education in a positive learning environment, which results in the vast majority achieving qualifications and acquiring skills and attributes that enhance their future opportunities.
"With regard to uniform, unfortunately despite contacting specific parents, sending some girls home to change, requiring others to wear a school-owned skirt for the day and repeatedly asking others to 'unroll' their skirts at the waist we still had some girls coming to school in inappropriate skirts.
"I have therefore introduced a trousers-only policy, which will enable my staff to focus their time and effort on providing pupils with the best education possible.
"We are not the first local school to come to the conclusion that all pupils should wear trousers.
"Kesgrave and St Albans High Schools already have a trousers-only policy, and discussions with staff at both institutions confirm that the change has made a huge difference for the better."
He added that since writing to parents about the decision only two had complained.
One of these was about financial circumstances, which the school has offered to help with. The other was from a parent who was not aware of the measures the school had already taken to address the problem.