It's about 2.30pm and lights are going out in primary schools all around the land. We're not talking about some energy-saving initiative to bridge the latest school budgetary shortfall. This is the effect of making key stage 2 kids work through the afternoon without a break.
When I was a lad, we had morning and afternoon playtime in the infants and the juniors. For that matter, we had an afternoon break at secondary school.
Apart from the poor souls stuck on a factory production line, it's difficult to think of adults who work for two hours without a break. OK, office workers aren't sitting in expectation of a bell to summon them to the playground. But by the time they've sloped off to the loo, popped to the coffee machine or taken a fag break, they've not done two hours.
If you were a boss who forced unrelenting effort out of employees, come the afternoon you'd find their energy levels, concentration and creativity dropping. Why do we think seven to 11-year-olds can manage?
In Ireland, most primary schools shut at 2.30pm. In Denmark, lessons end around 1pm. If they can manage with these hours, can't we give our kids 10 minutes to recharge their batteries?
Mornings are now almost exclusively given over to literacy and maths. Why? Because we know that if we try to teach English or numeracy in the afternoon, the children will be too tired, unsettled or in need of the loo to take it in.
The first hour after lunch goes pretty well - providing you can minimise the time spent discussing who wouldn't play with whom, who cussed whom, and why the boys can't play football on a Friday.
But, come the last hour, you can feel like a cowboy at the end of a long cattle drive. Your steers regularly need steering back on to the subject - they're more interested in telling their friends what they'll be doing after school. If you're lucky, you'll have been able to timetable in PE, art, music or design and technology.
I've found that hands-on science investigations work well in the afternoons. Role play and hot-seat activities also produce results. It feels like play and the children love it. Come the afternoon, we should be encouraging them to play, not memorise what happened to Henry VIII's six wives.
I know most teachers and heads will agree with this in principle, but will cite the pressures of fitting in government requirements for time allocated to each subject. But, for me, the compulsory daily assembly is the one thing that stands out as a waste of time when set against the need for an afternoon break. Whole-school get-togethers can be invaluable, to give a sense of oneness and as a simple communication exercise. But every day?
Assemblies can be an important snatch of non-contact time, too, if the head allows you to disappear once the kids are settled. They are also a good forum into which thoughts on morality, teamwork and friendship can be introduced. But they last 15 minutes, and then there's the time used in moving a whole school in and out of a hall.
Wouldn't we be better off allowing that time to be used for kids to get some fresh air, talk with their friends, blow off steam and generally escape from the pressure of lessons? Not only would they benefit, teachers wouldn't have to guess about those frequent afternoon requests to go to the loo. Are they genuine or is some rascal taking the proverbial?
David Ogle teaches at Poole's Park primary school, London borough of Islington