Teenagers often complain about early starts but, according to a top lawyer, students could launch legal challenges against schools or exam boards for forcing them to take exams in the morning.

Employment law specialist Kate Hindmarch said male pupils may be able to claim they have been indirectly discriminated against by being made to sit morning exams, because they are not at their most alert.

Teenagers and their parents could use research that indicates youngsters become less alert in the morning when they enter adolescence, a trend that appears to be more pronounced in boys than girls, she said.

The suggestion comes after Dr Paul Kelley, a sleep expert at the University of Oxford, said more than 90 per cent of youngsters became less alert in the morning as they entered adolescence.

“The body clock of 16-21-year-olds shifts dramatically by, on average, almost three hours,” he said. “So holding an exam at 9am is equivalent to a 6.30am exam for an adult.”

Dr Kelley told a group of parents attending a talk at North Bridge House Senior School, an independent school in North London: “Few adults would opt to sit a potentially life-changing test so early in the morning but that’s exactly what we expect of our young people.

“It’s unjust and it’s unnecessary. Exams should be designed to get the best out of people and to be fair. For this age group morning exams are neither.”

Ms Hindmarch, a senior partner in employment law at Langleys Solicitors, said that in order to make a claim against a school or exam board, a pupil or their parents would have to be able to demonstrate that they would have scored a higher result had the exam been taken at a different time of day.

“The burden of proof would be on the pupil to establish if they sat, say, their maths exam in the afternoon they would have got a better grade. They would have to show that taking it in the morning had had a detrimental impact on them.”

Schools do not decide on the timing of exams but Ms Hindmarch said a pupil or parent could challenge a school over its choice of exam boards if its papers were taken in the morning.

However, she suggested schools – or exam boards – should think twice before rushing to change exam times. “If you started moving exams to 2pm you could get girls saying, 'We do better in the mornings, so a later start time affects us disproportionately',” she said.

Jonathan Taylor, headteacher at North Bridge House, said: “We have introduced a later start for sixth formers and we’ll consider starting the school day later still if teachers and students feel the benefit.

“If all the research suggests that morning exams are having such a harmful effect on youngsters, then at the very least the exam boards should consider making A-levels afternoon-only exams.”

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