When schools have a uniform, teachers tend to walk around the building punctuating their journeys with a repetitive refrain: “Tuck your shirt in.Straighten your tie.Those aren’t regulation trainers.Your skirt is too short.” Is it worth the hassle? And more importantly, could a strict uniform policy actually create discrimination?

Many school websites set out formidable uniform requirements. For example, one stipulates “single-breasted black blazer with the school badge on the breast pocket; authorised house tie; traditional white shirt; black trousers, not jeans; black or navy pullover; black socks and shoes, not trainers or boots”. In addition, the school “expects that hair should be clean and tidy, not dyed or shaved”. It adds that the headteacher “may forbid any item he considers inappropriate”.

In the UK, this approach is supported by government rules stating that “the headteacher can discipline your child for not wearing the school uniform. Your child can only be suspended or expelled if they repeatedly ignore the uniform rules.”

Regulations elsewhere in the world also tend to support the right of schools to decide on their uniforms, as long as they do not discriminate based on gender, race, disability, sexual orientation or belief.

But what does the evidence say about uniform? Guidance from social mobility charities the Sutton Trust and the Education Endowment Foundation states that “there is no robust evidence that introducing a school uniform will, by itself, improve academic performance, behaviour or attendance”.

As a uniform is often introduced alongside other policies, it is difficult to isolate its effects. Anecdotal evidence suggests that introducing a new uniform in challenging schools can be seen as a public commitment to improvement, and there are some indications that they can improve attendance in high-poverty areas. But the findings are far from unequivocal.

Parents do have a route to complain about uniform, however. If they believe that their child is being discriminated against, they can take the issue to the headteacher. Likewise, if parents want to propose changes to the uniform, it is the duty of the school leader and the governors to listen to that request and give it proper consideration.

If the objection relates to money (rather than style or personal taste), schools must pay particular attention. The costs can be considerable with extensive uniform lists and this can make it impossible for a student to enrol at a particular school.

Blazer trail

There are safeguards in place in most countries, of course. In the UK, the Department for Education states that the school should give parents time to buy the right clothes. Parents who feel that they are being forced to use an expensive supplier are advised to seek advice from the Office of Fair Trading.

Schools also tend to have stores of uniform items that they can give to students who cannot afford to buy their own. At some institutions, parents are encouraged to donate old items and can even be paid a nominal fee for doing so. It could be worth investigating whether your school offers this service.

But even this may not be enough to ensure that your policy is as inclusive as it could be. Take, for example, the Australian school that made headlines for having a uniform list that was 18 pages long, with seven hat styles, five different bags and multiple accessories. It is unlikely that children from low-income families would feel comfortable applying there.

This is something that school leaders should consider carefully. Even if you believe uniform is central to the way a school operates and feel that it produces the best environment for students to learn in, this cannot be at the cost of excluding children, or singling them out because they cannot afford to buy a huge list of required items. In short, you must make sure that your school is open to everyone, regardless of what they wear.

Dr John Dunford is chair of Whole Education and of the Chartered Institute of Educational Assessors and is the UK government’s pupil premium champion

How to have an open uniform policy

• Be clear about the purpose of the school uniform.
• Incorporate dress code into the wider behaviour policy.
• The governing body should make decisions on uniforms, having consulted widely.
• Keep costs as low as possible.
• Ensure that items are available from several different shops, including the larger chains.
• Keep a stock of spare items.
• Ensure the commitment of all staff to enforcing the policy.
• Take great care when defining what religious dress is permitted and consult local religious leaders first.
• Word the policy statement on your website carefully - it speaks volumes about the school’s ethos.