Soon after that the second call came from someone who refused to give their name but said that Marsden and several other police officers had carried out the kidnapping.

Naturally all hell broke loose. Drummond tried to call Marsden but his mobile was switched off. He was among a bunch of officers who had worked through the night and had gone home to get some sleep. But when Drummond called his wife, she said he’d been out since this morning and she’d assumed he was at the office.

After that efforts were made to determine his whereabouts, and it didn’t take long. The GPS tracking on his car pinpointed its location in Peckham, just a couple of miles from Rotherhithe.

The assumption was made that if his car was there then so was he. Within minutes a rapid response team was deployed and Drummond hurried out of the office to go there himself. In his wake he left a team aghast at the extraordinary turn of events.

We all hoped that it wasn’t true, that Marsden hadn’t gone rogue. But I had a bad feeling that he might well have done. I recalled what he had said to me the morning after Marion Nash was murdered in her bookshop.

‘My money’s on Roy Slack … If it was up to me I’d do what the scumbag obviously did to that firearms officer, Hugh Wallis. Just lift him off the street and make him disappear.’

I agonised for a few minutes over whether to tell Drummond, but decided to keep it to myself out of a sense of misplaced loyalty.

I then discovered that he’d also made his feelings known to a few of the other detectives, including Janet Dean.

‘After the news came in about the Commissioner he really flipped,’ she said. ‘He started ranting about how Slack was making us look like a bunch of amateurs and that he shouldn’t be allowed to get away with it.’

‘So do you reckon he’s actually gone and done it?’

She shrugged. ‘I suppose we’ll know soon enough.’

We were still waiting for an update from Peckham, which was expected at any time. I decided to stick around even though Drummond hadn’t said I could return to work.

I sat at my desk, unsure what to do next. The office was suddenly much quieter. It was as though a heavy cloud had descended, stifling discussion and dampening the enthusiasm of every member of the team.

But they carried on working. Some were on their phones chasing down leads, while others were searching online for clues and information.