‘Mr Slack has asked me to provide you with all the information you require,’ consultant oncologist Peter Merrick told me. ‘I’m afraid that what my patient has told you is the truth. His pancreatic cancer will soon be at stage four and his life expectancy is no more than six months. But I suspect he’ll be dead long before then as his condition has begun to deteriorate quite noticeably.’

It was hugely significant, not just because it raised a question as to whether he remained a suspect in respect of the death threats, but also because we’d need to work out where the investigation into his firm went from here. Who would take over the reins? Would he wind down any of his illicit operations in addition to the legit businesses? Would his demise lead to a power struggle between rival gangs?

I found it hard to feel sorry for Slack. It seemed he was going to part this world without being punished for a life of crime. He’d built up and run one of London’s most powerful criminal empires. He’d been heavily involved in drugs, extortion, prostitution and money laundering. He’d established partnerships with Eastern European people smuggling gangs and at least one notorious Mexican crime cartel.

He had caused so much misery for so many people, but he’d be going to his grave content in the knowledge that he had got away with it. Two fingers up to the law. To all those officers in the Met who’d been unable to bring him down. It was wrong. Scandalous. Ridiculous.

Like hearing that a child killer has committed suicide in his prison cell while awaiting trial.

I rang Aidan just after seven o’clock and he told me that both he and my mother were going into work.

‘We can’t just sit at home all day worrying,’ he said. ‘For all we know this could go on for weeks.’

It was a frightening thought but I tried to play it down by telling him that it was very unlikely. I knew there would be no point urging him to stay at home behind locked doors. He’d already made it clear that he wasn’t prepared to.

He confirmed that a marked police car had been parked outside the house during the night but had disappeared about an hour ago.

‘They’ll come back later,’ I said. ‘And in the meantime I’ll see if I can get them to station a car outside the school.’

I then told him I’d stay in touch throughout the day and hung up.