Ella kept leaning forward to check their speed and she’d never seen the dial show anything faster than ten miles an hour. It wasn’t a difficult calculation. They’d started with enough petrol for fifty miles. That’s what the display had said once they’d got going. Fifty miles at ten miles an hour would take them five hours, and that was without all the mucking about getting on to the motorway.

‘We’ll use less petrol if we go slow,’ Robbie had explained when Ella questioned him about it.

Ella had been very nervous at first, as they’d nosed round the backstreets, trying a road, giving up, turning back, almost getting stuck. She’d been worried that at any moment they’d be attacked by grown-ups, but as the day had gone on and they hadn’t seen any, not one, she’d relaxed. The others relaxed too. She’d watched Maeve and Robbie. How Maeve had started out with her shoulders up by her ears and her head tight on her neck, and slowly she’d loosened up. Like she was melting.

Robbie too. He’d hissed and groaned at first, his bad leg hurting him. Now, though, he seemed comfortable. And every so often he would touch Maeve’s leg and she would smile at him.

He had a thing for Maeve. It was so obvious it was funny. Ella noticed these things. She hoped they weren’t going to get all gooey and cut her and Monkey-Boy out. She didn’t like it when people got girlfriends or boyfriends. They changed.

Seeing the two of them relax made her feel a whole lot better, though. Maybe they were going to make it. Maybe they really were going to escape.

Ella looked out of the window as trees and buildings slipped past. It was over a year since she’d been in a car. She’d forgotten what it was like. She remembered long drives with her mum and dad and Sam, listening to a story CD. Harry Potter or Alex Rider … Jacqueline Wilson if she could get her way.

As they moved further along the motorway, it seemed that the whole world was empty. They passed the signs to Heathrow Airport and Maeve said how amazed she was that Blue and the others had walked this far.

Yeah, thought Ella, they were probably walking faster than Robbie was driving.

And then they passed under the M25 and Maeve cheered.

‘What’s the M25?’ Monkey-Boy asked, seeing that it was important to Maeve.

‘It’s a motorway that goes all the way round London,’ Maeve explained. ‘A huge ring road. As far as I’m concerned, it’s the boundary, where London stops and the rest of the world begins.’