Jameson pursed his lips. ‘I’ve checked their birthplaces, but they’re spread across the UK. I’ll check their social media footprint again. Look for hobbies. I’ve started tracing previous jobs and am waiting for a call from an old mate.’

Bloom knew that when Jameson said ‘old mate’, he meant a contact with the highest level of security clearance. A person who could access most of the details of most of our lives, should they so wish.

The office phone began to ring.

‘That’ll be Geoff Taylor,’ said Bloom.

Jameson answered, pressed the speaker button and introduced himself. He was beginning to explain the background to the case when his mobile flashed on the table. Bloom saw that the incoming number was blocked and nodded for him to take it. It was probably his ‘old mate’. Jameson headed into the hallway and Bloom took over the phone conversation.

‘Can you tell us about Grayson’s disappearance, please?’ she asked.

Mr Taylor explained that his son had gone missing after meeting a girl on a night out. He’d hoped he was simply losing time in her student bedroom. But some of Grayson’s friends had tracked down the girl and she said she’d last seen him outside a club at the end of the night.

‘Have the police checked the CCTV?’ Bloom found it easier to gauge a person’s response over the phone. The lack of visual stimuli made it easier to detect a lie: the deceit was evident in what a person said – the hesitations, the lack of details, the inconsistencies – rather than in the tapping of a foot or a shifty look to the left.

‘Yes, but only on that street. They said that anything more would be a strain on resources. They saw Grayson walk away from the club, but not which way he went at the end of the road. They haven’t let me look at the footage. They told me, and I’m quoting here, “There’s literally nothing of interest to see.”’

Bloom exhaled … Nothing of interest to see. The insensitivity of some officers infuriated her. She understood that they became desensitized, but this footage could be the last sighting of Grayson. And, if the worst had happened, it might be Geoff’s final chance to see his son.

‘So you’re confident he walked away alone?’

‘That’s what they’re saying,’ said Geoff.

‘Tell me about Grayson, Geoff. There are four people who have gone missing and we’re trying to find out if they have anything in common.’

‘What do you want to know?’

‘What sort of person is he?’

‘He’s a very intelligent boy. He takes life seriously. I had a few problems with him when he was younger, right after he lost his mum, but we came through it and he’s grown into a fine young man.’

‘What kind of problems?’