‘Who else was going to look after him? He wasn’t my son, and Tony was never around long enough to take proper care of him. He was always travelling, or working – or hiding, if you ask me. Running away from his responsibilities. I tell you, it’s no wonder Ben turned out the way he did with a father like that. What is it they say? The apple doesn’t fall far from the tree.’

Ben’s stepmother stubbed out her second cigarette, even more viciously than she had the first.

‘Do you know of any difficulties Ben might have been having at Beaconsfield, Ms Johnson?’ said Fleet. ‘Any trouble he might have mentioned when he was home – perhaps problems between him and his friends?’

‘Friends?’ said Ben’s stepmother, scoffing. ‘Ben didn’t have any friends. And I told you, the only problem Ben had was Ben. He was angry, bitter, resentful. He wound people up. Deliberately, for the most part. That’s why he got kicked out of so many schools. He got into fights, swore at teachers, you name it.’

‘From what age did he start behaving that way?’ Nicky asked. ‘His mother – his biological mother, I mean; your husband’s first wife – died when Ben was seven, is that right?’

Ms Johnson reacted as though Nicky had said something funny. ‘I knew you’d bring it back to that eventually. People always do. That’s why Ben got away with so much for so long. The sympathy vote,’ she added scornfully. She shook her head. ‘But if you ask me, Ben’s mother getting cancer had nothing to do with it. He barely even knew her, so how can you use that as an excuse? And anyway, the way Tony told it, Ben was trouble from the day he was born.’

Ms Johnson pulled out yet another cigarette. The last in the packet, it seemed, from the way she tossed the box on to the coffee table. She clicked her lighter, and squinted at Fleet through the flame. Once her cigarette was lit, she jabbed the fiery end towards him.

‘You’re a policeman,’ she said, blowing out smoke. ‘You should know. Some kids are just born bad. And the way Ben wound people up … If you ask me, it’s a miracle nobody murdered him sooner.’

‘Well, that was edifying,’ said Fleet, once they were two flights of stairs closer to ground level.

‘Wasn’t it just?’ said Nicky. ‘Restores your faith in humanity.’

Fleet veered to avoid a puddle of something on one of the concrete steps. There was a stink in the stairwell that pinched at the bridge of his nose. He glanced over the banister, and noted how far they still had to go before they reached fresh air.

‘There’s a perfectly good lift, you know,’ he said to Nicky.