Here in Canada, we have a murderer of that class — Russell Williams, who was a colonel in command of the largest air base in the country. He kidnapped, raped and killed two women before he was caught, after a long career of creeping, peeping and snatching underpants off clotheslines. One of his victims was a corporal under his command. Only incest murder is worse.

The capture of Russell Williams is down to a brilliant detective of the Ontario Provincial Police, who secured a full confession leading to a guilty plea and a life sentence. But the shock of it still reverberates through the Canadian Armed Forces. In my last gummint job, the staff officer in the cubicle next to mine was reduced to tears at the news; Russell Williams had been his previous boss, and had given him the most glowing performance evaluation of his career. He says now that the very existence of that man’s name in his personnel record feels like a taint.

Yes, blokes in general really should check their privilege and attitudes with respect to women’s right just to be as they wish to be in the world. But some evildoers have such excellent camouflage that the rest of us can be forgiven for not spotting them as the predators they are.

That said, the killer of Sarah Everard must have showed his true colours at some point if the other guys in his unit nicknamed him “the Rapist”. Pity they didn’t realize that their eyes were not deceiving them, and that it was no joke.