That was the other thing that people didn’t like about Janet Dean. She too often boasted about how well off she and her husband were. They lived in a town house in Chelsea, owned two BMWs, and their latest acquisition was a cabin cruiser that was moored in Brighton marina.

Of course, their lifestyle wasn’t funded by her copper’s salary. Her husband worked for an investment company in the City, although she’d always been vague about exactly what he did, and kept schtum about how much he earned.

I was on my second G and T when DCS Drummond decided to propose a toast to the team’s latest success.

‘You’ve all done a great job and I’m proud of you,’ he said. ‘But make no mistake – things are about to get much tougher. Roy Slack is a master when it comes to evading prosecution. And there’s no one who’s as cautious as he is at avoiding surveillance. As you know from the intelligence packs you’ve been given, he uses unregistered mobiles and employs debugging devices in his home and office. He also has powerful friends and we suspect there are officers in the Met who are in his pocket. Those are among the people we aim to flush out during this investigation.’

We all knew it wasn’t going to be easy. Slack was London’s longest established crime boss and it was strongly believed that he had connections with senior officers, the Crown Prosecution Service and several MPs. It was one of the reasons he had managed to reign supreme for so long.

‘When we get together tomorrow I’ll give a full briefing on our approach,’ Drummond said. ‘But one of our main lines of enquiry will continue to be the disappearance of firearms officer Hugh Wallis. I still believe that it’s highly likely that Slack had something to do with it, despite his denials.’

Officer Wallis had vanished while returning to his home in Shoreditch from a late shift just a week ago. His car was then found the next day parked behind a warehouse a few miles away in Stratford. The keys were still in the ignition.

No one had heard from him since his disappearance and no clues to his whereabouts had been offered up by traffic cameras and CCTV.

According to his wife there were no issues in his life that he might have decided to run away from. It was therefore feared that something bad had happened to him.

The task force had been alerted because Wallis had been involved in a joint operation that had been mounted three months ago with the NCA. Raids were carried out on the homes of twelve known villains, including a man named Terry Malone, who worked for Slack.