Without a word, Jack walked away. He wasn’t going to get anything remotely useful from George Barrowman in his current frame of mind, so he went in search of Sally instead. In the kitchen, Sally was preparing a large but very healthy breakfast. She was a sophisticated-looking blonde, wearing designer clothes, probably in her mid-40s, but the likelihood of cosmetic surgery made it hard to be sure. She was slim, toned and barefooted, with toenails painted bright red and Jack was surprised to see that she wore a toe ring and ankle bracelet. Clearly Sally Barrowman had been a freer spirit in her time.

She saw Jack looking at her. ‘Mathew has Prader-Willi Syndrome on top of his autism,’ she explained. ‘He has no trigger that says “I’m full. I should stop eating now.” He just carries on. It’s more complicated than that, of course, but that’s the gist of it. It gives him the habit of biting the inside of his mouth until it bleeds and chewing the skin around his fingers.’

Jack nodded sympathetically and looked around the extensive kitchen. Everything was exactly where it should be, and every surface shone like new. Certain cupboards had locks on them, as did the fridge. Nothing in this room was homely; it was clinical, like a lab. And as Sally weighed some porridge oats, Jack thanked God for his small ‘happy mess’ of a kitchen. He was just about to ask Sally a question when he heard George Barrowman’s angry voice.

‘Did you just walk away from me?’

Jack glanced over his shoulder, purposely not bothering to fully turn and face George. ‘Yes, sir, I did. I decided that yours would not be a productive interview right now, so came to see if I could chat to your wife.’

George came and stood right in front of Jack. ‘How dare you presume to do anything in my home without my express permission!’

‘Mr Barrowman,’ Jack replied calmly. ‘If I’m to ask your permission before I can make a move, I’ll head back to London now.’ Sally froze, mouth open, with a spoonful of oats hovering in the air. Jack continued whilst he had George’s full attention. ‘I’ll be respectful of your position, your property and your family, sir, but I won’t be slowed down by unnecessary formalities.’

Stumped by Jack’s firm response, George then resorted to the oldest cliche in the book. ‘I want the name of your superior officer!’

‘DCI Simon Ridley of the Metropolitan Police is not technically my superior, but if you want to speak with him, you can use my mobile. His direct line is in there.’