Mallory visibly flinched at the profanity.

‘I want at least an hour with him.’

‘We’ll give you five minutes,’ Swire said. ‘But any sign of aggression and he’s coming down.’

Gane returned the reporter’s mobile with the tracking device.

‘What’s in there?’ Mallory said.

‘In the end I went for the handset-based software,’ Gane said. ‘It’s more accurate than a SIM card with an iPhone.’

Mallory still didn’t look happy.

‘Let us know as soon as he makes contact,’ he said. ‘Don’t wait for us to pick it up on your switchboard.’

‘Of course,’ Bush said. She threw her phone into her bag. ‘I’ll tell you where we’re meeting and I’ll see you there.’

She left, escorted by the chief super, and for a moment I thought I was going to hear Mallory curse for the first time. Instead he ran his hand over his polished skull and said angrily, ‘And I want the lot of you in a Kevlar Stealth!’

In the only quiet corner of MIR-1, Dr Stephen was at his laptop. I walked over to him and saw that he was staring at Bob the Butcher’s timeline. The forensic psychologist looked thoughtful. The mushroom cloud was still there.

‘Those people in Hiroshima,’ Dr Stephen said. ‘They had been expecting a massive bombing raid for months. But what they got was the end of all things. What they got was a new world.’

‘So what does it mean?’ I said. ‘The cloud. What’s he trying to tell us?’

He shook his head.

‘I’d be making a guess,’ he said.

‘Go ahead.’

‘The designated target,’ he said. ‘It’s been chosen.’

The internet café was on the Holloway Road. Wren and I sat on opposite sides of the room while half a dozen weary-looking foreign students checked their mail and Skyped home. It seemed a strange location for Scarlet Bush to meet Bob the Butcher.

And when I heard Gane curse in my earpiece, I knew they never would.

Wren heard it too. She looked over at me and I shook my head.

In the back room was a group of armed officers looking like soldiers from the next century. They wore black rubber goggles, Ballistic Kevlar helmets and shiny boots. They carried Heckler & Koch assault rifles, Taser X26 guns and CS gas spray. Their mouths were thin lines of frustrated adrenalin. Mallory and Whitestone were to one side hunched over Gane and his laptop.

‘What’s happening?’ I asked them.

‘We’ve lost Scarlet,’ Mallory said. ‘Not the signal from her phone. Just her.’

‘She gave our officers the slip at her paper,’ Gane said, not looking up from the screen. ‘Went out the fire exit, we think. That easy.’

‘Wanted some quality time on her own with Bob,’ Whitestone said.