Thirty pupils at a Canterbury secondary school were held in detention this week after turning up for lessons without proper uniform.

St Anselm’s took the action after warning pupils and parents at the end of last year that it would be enforcing its policy to the letter – especially on footwear.

But when 30 pupils arrived with black trainers or canvas shoes on Monday, the school held them back for an hour.

The move comes in the wake of the furore at Hartsdown Academy in Margate where police attended a protest by parents outside after children were sent home for having the wrong uniform.

Mike Walters, who is head of St Anselm’s, in Old Dover Road, said yesterday that when the new academic year started last week the school warned pupils they had a week to ensure they were properly dressed.

“Unfortunately, while 880 children arrived in school on Monday morning with the correct footwear, around 30 did not and they were sanctioned, as we had warned they would be,” Mr Walters said.

“We do not wish to have to sanction children over their choice of footwear but we are determined that the school uniform will be worn by all.

“We were concerned at the end of last term that some children had begun to wear shoes that were not appropriate or safe for school, including black trainers and shoes made of canvas.”

Mr Walters says the drive to enforce the dress codes is aimed at raising academic standards by limiting distractions.

He went on: “We noticed a very small number of children wearing incorrect footwear towards the end of last term and decided to remind all pupils and parents of the expectations in advance of the new school year.

“The pupils in the school generally look immaculate in their uniforms and this helps them to focus on their work without unnecessary distractions related to their dress.”

The school’s letter to parents at the end of the summer contained information about what exactly was acceptable and what was not. Banned clothing includes hoodies, denim items, trainers and skin-tight trousers.

One parent of a pupil at St Anselm’s complained that the school was being “heavy-handed” over its uniform regulations.