‘But that’s exactly what’s happened,’ an analyst replied, in a morose voice. ‘Just take a look at that.’ Angela glanced up at one of the screens where the grainy, black-and-white live feed was coming in from one of the CTSFO’s chestcams. It said it all. It showed an empty, deserted warehouse, an empty side office and, most troubling of all, the canisters were gone. There was no one around, not a soul. It was a Mary Celeste moment.

The senior investigating officer stood in the centre of the room and clapped his hands to gather everyone’s attention. ‘Listen up,’ he said, his voice grave and authoritative, ‘there’s no point moping over missed opportunities. We don’t have that luxury. We need to pin down where they’re heading, get blue lights to close off their exits, then let Counter-Terrorism deal with them.’

‘But what about the virus?’ Angela asked. She had a terrifyingly clear vision of a team of fanatical extremists driving along the darkened roads of southern Britain with a lethal pathogen onboard. The implications were almost too awful to consider. ‘Surely we need to—’

‘Yes, we do,’ he cut her off, the impatience showing in his voice. ‘We’re alerting the Joint Biosecurity Centre of the risk to the public. Now, King’s Cross station,’ the SIO continued. ‘We have to assume that’s still their destination although …’ he paused to grimace ‘… they might be tempted to release it anywhere now. Carlton mentioned they’d considered other targets: a centre for migrants and so on. And let’s not forget there’s Stansted Airport just down the road. Met and Essex Police are putting in protective security. But this is where you analysts play your part.’ He was looking at three specific people in the room now. ‘Your assumption – and I concur with it – is that WaffenKrieg90 have invested too much planning and preparation in this to want to switch locations at the last minute. But in case they do,’ the SIO held up his index finger, ‘teams have also been dispatched to every mainline station in London. We’re taking no chances.’

‘And Tube stations?’ asked a case officer.

‘Becky, it’s nearly two in the morning,’ he retorted, giving her a tired look. ‘The Tubes don’t start running again till five.’

‘Still,’ persisted the case officer, ‘shouldn’t we be sealing them off? What if they’re looking to plant the devices on timers in a ticket hall? Or set them off remotely?’ She looked round the room for support, but the SIO chose to ignore her question and, instead, he clapped his hands again.