Porter fumbled in his jacket pocket and pulled out his warrant card. As he held it up to the glass eye of the intercom camera, he looked over his shoulder and gestured to Styles with his free hand that he should join him at the gate. There was a soft click followed by a low buzzing noise. Porter placed one hand on the gate and gave a tentative shove. It gave before him and swung open.

The short driveway looped around in a tight semicircle, passing the front door and curving back round past the garage doors, and exiting out through a second wooden gate. Porter and Styles walked almost shoulder to shoulder towards the door. It opened before they were halfway there, just six inches at first, then swung slowly until it was halfway open. Porter assumed the face that peered out was Mrs Locke herself, although if she could afford a house like this she may well have a maid.

From what he had read at the station, she was seventy years old, but she could have passed for a decade less. She reminded him a little of a younger version of Mary Berry, her short sandy hair cut just above shoulder length and tucked back behind her ears. Her eyes were a startling blue that demanded attention, but her body language screamed timidity, not the confidence and poise that often radiated from someone of her relative affluence.

‘Mrs Locke?’ asked Porter, just to be certain.

‘Yes, I’m Mrs Locke,’ she answered hesitantly. ‘Can I ask what this is about? Has something happened to Alexander?’ She spoke softly, with an accent that would cost a small fortune at elocution lessons.

‘Alexander?’ said Porter, looking to Styles and back to her.

‘My husband.’

‘No, Mrs Locke. This has nothing to do with him. I’m sure he’s fine. Could we come in for a few minutes?’ said Porter, looking past her into the house.

‘Of course, please, come in.’

She stepped aside to let them in, closed the door and turned to face them. Porter noticed that she seemed uneasy despite being on home turf, but then again the majority of people went through life without ever having the police turn up on their doorstep, and he put the vibe down to a simple case of nervous anticipation.