It’s a truism in policing that witnesses and statements are fine, but nothing beats empirical physical evidence. Actually it isn’t a truism because most policemen think the word ‘empirical’ is something to do with Darth Vader, but it damn well should be.

Not being invited in is one of the boxes on the “suspicious behavior” bingo form that every copper carries around in their head along with “stupidly overpowerful dog” and being too quick to supply an alibi. Fill all the boxes and you too could win an all-­expenses-paid visit to your local police station.

If you find yourself talking to the police, my advice is to stay calm but look guilty; it's your safest bet.

She had the startled-rabbit look that civilians get after five minutes of helping the police with their inquiries. If they stay calm for too long it’s a sign that they’re professional villains or foreign or just plain stupid. All of which can get you locked up if you’re not careful. If you find yourself talking to the police, my advice is to stay calm but look guilty; it’s your safest bet.

There was also a great absence of people, including behind the mahogany-topped reception desk. Now, there’s a time when an unlocked premises is a positive boon to a police officer as in – I was just looking to ascertain the whereabouts of the proprietor when I stumbled across the Class A controlled substances which were in plain sight in the bottom drawer of a locked desk in an upstairs office, M’lord.