How to spot them: Easily identified by their malodorous scent. Often flanked by the only empty treadmills in the gym.

You’re in the gym, you’re working out, so it’s highly likely you’re going to sweat. But, get this – fresh sweat doesn’t smell bad. So there’s no exercise-related excuse for that face-melting odour emanating from BO Bob and Reeking Rachel…

Instead, their peculiar funk is a heady cocktail of re-used gym kit, mangy hair and stale perspiration. Bleee.

All you can do is hold your breath and extol to them the virtues of the gym showers, offer a spray of Sure in the changing room or, if all else fails, activate the emergency sprinkler system.