‘Mr Gillard. I am a very patient woman, but I am not well these days, and I want to plead with you to reinvestigate the killing of my Robert.’

‘I’m terribly sorry. I would love to be able…’

Mrs Fenwick’s voice broke as she heard what must sound to her like bureaucratic buck-passing, certainly not for the first time. He knew it would be pathetic to have to tell her why his hands were tied. Following a reorganisation in 2010, the Met Police had been put in charge of the area where her son disappeared, and any reinvestigation would be down to them.

‘Mr Gillard, please. I beg you. You have no idea of a mother’s pain. It just never ends. It really never ends.’ There was a long sniff at the end of the line, and then sobs. The caller who had begun so confidently, reading her prepared remarks, was now lost for words. Gillard waited out the tears, feeling utterly wretched that he couldn’t help. He wondered what he could say to calm her, but realised it would take senior intervention to let him look again at what was now classified as a Met Police cold case.

But that didn’t mean he shouldn’t try.

‘Mrs Fenwick. I’m rather tied up investigating who it was that was found dead in the Thames recently. You may have heard about that. However, I can promise you, that as soon as I have some spare time, I will personally ask the chief constable to let me look again at Robert’s disappearance.’

After half a minute during which she struggled to maintain composure, she managed to rasp out one final croaky comment. ‘Thank you for that, thank you. I’ve had more than three decades of grief, but not a single second of justice. I hope you can put that right.’

‘I will do my best.’ Don’t get your hopes up, he wanted to say. Please don’t get your hopes up.

‘One more thing,’ she said. ‘Although I’m Robert’s mother, I changed my name after he disappeared, and moved house to get away from the fuss. So I’m using my maiden name. Which is Tilling. Mrs Poppy Tilling.’

‘Ah, I think I know your son, Gary.’

‘Yes, he does very well in his laptop repair business. As you know, he’s always helped the police with, you know, indecent images that he finds on hard drives.’

‘Yes, we’re very grateful.’

‘He’s a good boy, and though I’ve been bedridden for years, he looks after me.’

‘I’m glad to hear it, Mrs Tilling.’