And my job in respect of this new case was to focus on the main man – Roy Slack. It was the same brief I’d had on the last investigation, which was why I’d been one of the two officers sent to arrest Harry Fuller, the other being Martin Weeks.

This time Drummond had teamed me up with Kate Chappell because Martin had since moved over to the National Crime Agency. I was happy with that; Kate too.

‘I want you to dig up as much as you can on Slack’s private life,’ Drummond said to both of us. ‘For instance, we know he has at least one mistress. But are there others and can we get anything out of them? And what about his enemies? I’m struck by the fact that in the past so little was done to squeeze them for information. So draw up a list of those you think we should talk to.’

He told us to arrange for surveillance to be stepped up on Slack and his top henchmen.

‘We’ve been watching his flat in Canary Wharf and his office in Rotherhithe,’ he said. ‘But it hasn’t been round-the-clock because we’ve been short of people. From now on we need to know where he is and what he’s up to 24/7.’

‘What about the text message and the threat to kill us all?’ I said. ‘Shouldn’t we go and ask him if he knows anything about that?’

Drummond shook his head. ‘I don’t see the point at this stage. Even if he did arrange for it to be sent he’ll only deny it.’

‘But we could use it as an excuse to seize his phone and laptop.’

‘We had him in under a week ago after Officer Wallis disappeared,’ Drummond said. ‘As you know he was questioned for several hours and his properties were searched. If we haul him in again this soon without any solid new evidence then his lawyers will go ape-shit. So I think we should hold fire until we have something concrete to confront him with. Besides, the techies are still trying to find out where the message came from and it’s only fair to give them more time.’

I wasn’t happy with that and I could tell I wasn’t the only one. The threat we had all received was still hanging over our heads like a dark cloud – and there seemed no prospect of it going away anytime soon.

On the way home I saw my first Christmas tree. It lit up the window of a charity shop close to the tube station in Balham.