And finally…expert calls for UK employers to ditch 9-to-5 for later start times

Dr Paul Kelley, a former headteacher and sleep researcher, who initiated a start time of 10 am at his school in the north east of England, has now said workplaces adopt the practice and let staff start later – to make them more healthy and productive.

Dr Kelley, the former headmaster of Monkseaton community school in Tyneside and researcher in sleep science, said: “Across the western world, adults are averaging 6 and a half hours sleep a night during their working lives, when science shows we need at least eight.”

Dr Kelley, author of Body Clocks, says that a start time of 10 would be fairest to everyone – and would cut back on the epidemic of sleep loss.

Speaking to the Sunday Times, Dr Kelley said the ‘best’ time for some workers to start could be as late as midday.

The researcher published a new book, Body Clocks, which identifies five types of sleepers, ranging from ‘definitely morning’, to ‘definitely evening’.

Dr Kelley added: “Start times of 10am are the fairest (and best) if everyone had to choose a single start time. That would reduce sleep loss for the population as a whole.

“This would have an immediate positive impact on current levels of adult sleep deprivation caused by early workday start times. ‘It would reduce sleep deprivation by 70 per cent to 36 minutes on average a day.”