ou’ve got about three seconds to get rid of this guy. One second as he opens the door. One second as he comes through it. And one more second as he comes towards you, flexing his fingers and snorting through his nostrils. And it’s in that third second that you try a desperate tactic. You go into your best kung-fu pose, standing on one leg, with the other leg sticking out straight in front of you.

‘Stop right where you are!’ you cry dramatically. ‘Stop, or I’ll have to hurt you!’