Locke nodded. ‘I’m a man of my word, George, but how exactly do you propose we make good on our plans with him wandering round my house?’ He pointed at Porter. ‘He’s not exactly going to sit here quietly and count to ten before he comes looking for us, is he?’

Porter pushed his back against the cupboard, IKEA’s finest creaking as he did. Campbell extended the hand with the gun another few inches. ‘Stay put, Porter.’

‘Think about this, sir,’ said Porter, formal address feeling somehow wrong tripping off his tongue as he looked at Campbell, seeing the barrel twitching but never leaving his centre mass. It reminded Campbell that he was an officer, or at least Porter hoped it did. He touched a hand to the back of his head as he spoke, pushing against the mini egg that had already risen. ‘I called for backup before I came. None of us are walking out of here any time soon.’

Campbell gave a little smile, like a child who has just outwitted an adult. ‘Nice try, Porter. I would have remembered something like that coming over the radio on the way here.’ He pressed the heel of his free palm to his forehead, wincing as if with a headache. ‘I just need to think.’

‘If that’s what you believe, sir.’ Porter persevered with the weak bluff, but he knew it wasn’t fooling anyone. ‘Look, I don’t know what he has on you that’s put you here. That doesn’t matter. All that matters is doing what’s right. It’s never too late to fix things.’

Campbell closed his eyes, shaking his head. Porter considered making a lunge for the gun, but his head hadn’t fully cleared and he wasn’t sure he could get the momentum from down on the floor.

‘Of course it’s too bloody late, you fool. It’s thirty years too late,’ Locke snapped. ‘Now pull that fucking trigger or I’ll come over there and do it myself, and you’ll be the next one staring down that bloody barrel.’

Porter’s dry mouth and spinning head made for something close to a hangover, but Locke’s words worked like smelling salts. Thirty years too late? His eyes widened, hand coming away from his head, pointing at Campbell.

‘You were … thirty years ago … You were there. You were the fourth man she saw. You were there the night Natasha died.’ He realised his mistake as he said the words, even as he saw the truth of them in Campbell’s face.

‘She?’ Locke spat out. ‘She? That silly bitch put you up to this, didn’t she?’ He gritted his teeth, this time more in anger than pain. Porter hoped Mary Locke was anywhere other than in this house somewhere.