Outraged parents are demanding answers from a school that kept up to 100 children out of lessons on their first day back.

Hertswood Academy, in Borehamwood, demanded that students who had not purchased their clothes from Stevensons, a uniform supplier, remain in the gym all day.

Skirts and trousers from the store cost between £17 and £30, incensing parents who said similar items can be bought from supermarkets, for a fraction of the price.

Pete Middlehurst, whose 13-year-old daughter attends the school, said: “I can’t afford to spend £25 on a school skirt. I bought my daughter a similar one from ASDA for £7, and then she wasn’t allowed to attend any of her lessons.

“When I heard she’d been called out of class, I was so shocked. I tried to call the school a number of times, but none of the teachers would talk to me.

“This is her GCSE year; she can’t afford to be out of class all day. She wants to work hard and become a psychologist. When she said that to her teachers, they just kept repeating that it wasn’t their problem.

“Nobody knows what is going on and I don’t know what will happen if she wears it again.”

Children were told to read books and complete worksheets while in the gym, but Mr Middlehurst said none of the teachers seemed to know what to do.

Hertsmere councillor Michelle Vince, who represents Cowley Hill, described the situation as a “total fiasco”.

She said: “In this economic climate, times are hard enough. Schools should not be making things worse.

“It’s ridiculous to have such an elitist system in a comprehensive school. The whole idea behind uniform is that everybody looks the same. - It shouldn’t be about segregating children based on whether or not they can afford a certain uniform.

“No one in the school will talk to me about what is going on, and the whole situation is a total fiasco. At one point they tried to deny that children had been forced to stay in the gym, despite parents telling me there were up to 100 in there.”

According to Cllr Vince, Hertswood Academy said they were expecting a delivery of trousers and skirts and anybody in the gym would be given the clothing, and their parents would be sent an invoice.

She said: “ I couldn’t believe it – it’s beggar’s belief.”

According to Cllr Vince, the school has now reversed this decision and said the children can have the clothes for free.

It has also amended its policy and said children can wear alternative clothing, so long as teachers “are not able to tell”.

But Cllr Vince thinks more need to be done.

She said: “We need what is and is not allowed, in writing. We can’t have children going to school not knowing whether or not their uniform is acceptable, with parents fearing that in a week or two someone will notice their child’s skirt isn’t from Stevensons.

“These parents aren’t annoyed that children to have to wear smart uniforms, it’s not about that. They just don’t see why they have to pay such high prices.”

Hertswood Academy were contacted for a comment but had not responded when the paper went to print.