Teaching unions have reacted with anger after staff at an Islamic free school were told they had to wear the hijab even if they were not Muslim.

It was also claimed that teachers were dismayed that girls at the Al-Madinah School in Derby are required to sit at the back of the class raising fears over possible discrimination.

Staff were reportedly spotted removing their headscarves as they left the premises at lunch time and claim they have been instructed not to wear jewellery or bring non-halal food with them to work.

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The school, which is currently under investigation by the Department for Education over alleged financial irregularities, caters for 200 students aged between four and 16.

Sue Arguile, branch secretary of Derby National Union of Teachers, said five teachers had raised concerns over changes introduced to contracts this summer.

“There are worries over practices concerning the discrimination between male and female pupils in the school, with the girls being told to sit at the back of the class regardless of whether they can see the board properly.

“This school was first launched as based on Muslim principles and not as a Muslim school. If the school is not sticking to the original reasons behind why it was set up, then it does call into question whether public money is being used properly and for its intended purpose.”

When it was founded last year it was claimed that half of students would be non-Muslim at the fully-subscribed school – one of two free schools established in the city.

Al-Madinah describes itself as having a “strong Muslim ethos” which it said would “give the school its uniqueness integrated with shorter holidays and longer school days to maximise opportunities for pupil achievement and success.” No one at the school responded to requests to comment on the claims.

Acting principal Dr GS Wilson has written to parents dismissing claims that the school was going to close down or start charging fees.

“Like all pioneers, we are on a journey, and as a new school open for just one year (and only a few days in our new, wonderful, secondary building) we simply ask for time to get going and grow into an excellent school,” he said.

A Department for Education spokeswoman said: “Schools and colleges have the freedom to set their own uniform policies.”