In a country where more than 40% get less than six hours’ sleep a night and millions nap at work, new ways to grab forty winks are big business

For many of us, it is a daily ritual. The eyelids grow heavy as the after-effects of lunch kick in. The head slumps forwards, only to recoil, ideally before anyone in the office has noticed. Energy levels are at rock bottom. The afternoon dip is here. And resistance is futile.

The Spanish have their siestas and millions of French people exercise their right to a postprandial power nap. The Japanese equivalent is the hirune – an afternoon snooze that goes some way towards compensating for their lack of sleep.