She left Jamie on his own and left the flat. She was gone for over half an hour, leaving him twiddling his thumbs, wishing he had his cigarettes with him. He chewed his fingernails, trying to work out another way to get into the flat if Mary couldn’t help him. What was she doing? He had a sudden horrible feeling that she had gone to tell Lucy and Chris what he planned to do; that she was colluding with them. A minute later she came back, and he realised he was being paranoid and ridiculous. She had Brian with her.

Jamie stood up and Brian said, ‘Mary’s just explained everything to me. I just feel sorry that I didn’t know about it before.’

Jamie shrugged. ‘It doesn’t matter.’

‘You should have told us, Jamie. We might have been able to help.’

‘I didn’t know you well enough, and anyway, nobody I told ever believed me. Apart from a friend at work.’ Yes, and his attempts to help had ended disastrously.

Brian nodded. ‘We’re here to help you now. We don’t want people like that living in these flats. It makes me feel ill. I quite understand your need to gather evidence, so’ – he looked at the ceiling – ‘as much as it will pain me to have those people eating from our plates and drinking from our cups, Linda and I will invite them to dinner. We’ve always got on alright with them. Obviously, we’re lucky that we don’t live in the flat directly above them.’

Jamie took hold of Brian’s hand and shook it. ‘Thank you so much.’

Mary said, ‘How will you get into the flat?’

‘I don’t know. I can’t break in because I don’t want them to know I’ve been in there.’

‘I think we can help on that score too,’ Brian said. ‘An elderly couple used to live in the basement flat.’

‘Mr and Mrs Chambers,’ said Mary.

‘Yes, and Linda and I were very good friends with them. It was very sad: Mr Chambers died and Mrs Chambers ended up in a home. Anyway, they were quite forgetful – a bit of a scatty old couple, actually. They locked themselves out a couple of times. In the end, they gave me a key in case they did it again. I’ve still got it. I know I should have given it back when they moved out, but I forgot. Luckily.’

‘Problem solved,’ said Mary.

‘Assuming the Newtons accept our dinner invitation.’

Jamie waited while Brian went upstairs and looked for the key. A few minutes later he returned and handed it to Jamie. ‘I just hope they haven’t changed the locks. If you go back to your flat now, I’ll call you and let you know if they’ve accepted the invitation.’

‘OK.’