Pupils have been banned from lessons and police were called after Sidcup school leavers turned up to their last day with ‘sequins on their collars and bows on their socks’.

Year 11 students at Blackfen School for Girls in Blackfen Road were allegedly turned away due to uniform alterations that do not comply with school rules.

One parent, who wished to remain anonymous, said: "It is their last day today, they have all got their uniforms on but some of them have put sequins on their collars and bows on their socks which doesn’t comply with uniform.

“They’ve left all of them to roam the streets, they called the police, they had a meat wagon outside.

“The girls have been in education for ten years, they have all turned up to school, and they want to do their lessons. You’ve got 40 girls roaming the streets, it is not safe, especially in this day and age.

“I think it is absolutely crazy on their last day, I just don’t believe it.”

A spokesman for the Metropolitan Police confirmed they were called at 8.35am as traffic was disrupted by the large group of students gathered outside the girl’s school.

Outraged pupils have taken to social media to vent their frustration.

One wrote on Twitter: “How is Blackfen not letting year 11s into school because they've decorated their uniform, [it] gets worse and worse every year.”

Another said: "My school wouldn't let year 11 leavers decorate their uniform, but of course they did, and now they're not letting them in school, pathetic

“No literally they won't let them through the gate and all the girls were just standing and shouting so they called the police

“They aren't exactly going to all go home and get changed are they, their uniforms are decorated.”

Head Teacher Matthew Brown said: "We are sorry that some of our year 11 students chose to turn up out of uniform today and so were unable to come into school.

"The whole year group were asked earlier this week to come in uniform today as usual and they were clearly told that if they didn’t they would be asked to return home to change.

"Many of the girls that turned up this morning did just that and have since come back into school.

"We know that the end of school is a celebration and recognise that the girls have worked hard at Blackfen.

"To mark this we will be holding a special event after the exams next month.

"We hope all the girls will come along and have a great time remembering their school years.

"We are delighted that many of these students will also be staying with us into 6th form."