The reality of it was only now just hitting him. The realization of just what a huge area they had to cover. Having the car was a bonus, but still, when it came down to it, this was a fairly hopeless mission. Living in London, hemmed in by buildings on all sides, you lost the sense of how big the world was. How much there was of it. Driving out of London along the M4, Ed had watched the world unfold and open out. First houses and office blocks and factories had whizzed past, then they’d started to see trees and greenery, grass and bushes, the beginnings of the countryside, and then wide-open spaces.

And all along the way they’d seen sickos – sentinels – standing in the road, eyes closed, arms raised, faces turned up to the sky, skin burnt and blistered.

‘Why they doing that?’ Lewis asked as he drove round one standing in the middle of the motorway.

‘They’re carrying the signal,’ said Trey. ‘Like telephone poles.’

‘What signal?’ said Lewis. ‘What they saying?’

‘It’s not words,’ said Trey. ‘It’s more like a hum, a buzz, a homing signal.’

‘Who’s it for?’

‘They’re gathering, I reckon,’ said Trio.

‘I don’t like them,’ said Ebenezer. ‘I hate them.’

‘We should run them down,’ said Kyle.

‘Yeah,’ Macca joined in. ‘We should go GTA on them.’

‘We’ve got to keep moving,’ Ed protested. ‘Not waste time. If we stop to deal with every stray sicko we see we’ll never get anywhere.’

Indeed, there seemed to be sentinels every few hundred metres, even out here on the motorway – mothers, fathers, teenagers … Ed calculated that if they were like this on all the roads leading out of London there must be thousands of them. And how many more were they calling in?

He remembered the conversation he’d had with Shadowman when he’d gone to get the alcohol off him.

‘You really gonna head out west and look for this girl?’ he’d said, incredulous.

‘I owe it to Sam.’

‘If it was me I’d either tell him to shut it or I’d lie to him,’ said Shadowman. ‘Pretend I’d looked. Give it a day or two then go back and get on with your lives.’

‘Well, you’re not me,’ said Ed.

‘No,’ said Shadowman. ‘I’m not. You’re like a dad, Ed. You think you need to look after everyone and keep them safe. But you can’t look after everyone. You’ll end up going crazy. And, besides, we need you here.’

Shadowman had told him all about the sickos’ general he called St George, who seemed to be gathering all the grown-ups in London.