As DI Wilson appeared to contemplate this, McNab had a strong feeling that the boss already knew the whole story – who from, he had no idea, although the thought did strike him that it might have been from Ellie herself.

‘And when were you getting round to telling me this?’

McNab hummed and hawed in silence for a moment. Eventually he found some words.

‘That’s why I’m here, sir, to tell you what happened. Harry left me a message when he signed out of the discharge lounge. An eight-digit number. We think it’s a service personnel identification, which might be a lead to the Sandman’s operations.’

This pronouncement, which had come out of his mouth unexpectedly and which he had never intended to make, now hung in the air between them.

The boss, who never reacted without thinking, said nothing for a moment, then, ‘You think the Sandman may have a service personnel set-up?’

‘It’s a possibility, sir,’ McNab said, although the thought had only just entered his head. ‘McArthur was a serving soldier, probably discharged for using while in Afghanistan. What if he was doing more than just using when out there?’ McNab said, warming to his theme.

The boss had already moved to the window and was looking out over his beloved Glasgow.

‘So, the Sandman could be bringing it in via army personnel.’ He began to think out loud. ‘It’s happened in the USA. Returning troops bringing in drugs and money from war zones, hidden in returning equipment and vehicles. The mess in Afghanistan has been going on under the radar forever. Never on the news. Too embarrassing for the government to admit or reveal. It’s as big as, or even bigger than, the human trafficking we’re having to deal with.’

‘Yes, sir,’ McNab felt obliged to say.

‘And the Skye victim?’

‘Paul Watson, probable associate of Malcolm Stevenson. Previously jailed for dealing, sir.’

‘By you, when you were a DI,’ the boss reminded him.

McNab was sorry he’d let the boss down, but the truth was he was glad he wasn’t a DI any more. No more focusing on the rules. If he hadn’t dropped down a rank, he’d have probably left the force altogether. Under a cloud, no doubt.

Which I might yet manage to do.

‘As I recall, he had a foothold in Skye? So why was he back there?’

It was a question McNab had been asking himself since Janice had revealed the DNA results. McNab had a sudden thought that he might indeed be on his way to Skye. In that, however, he was to be proved wrong.

‘Find out who owns that service number, Detective.’

‘If it’s a serving soldier, we’ll need MOD permission to access their records,’ McNab said.