‘Bish darling, do you know anything?’

His mother had never been much of an alarmist but he could hear the fear in her voice now.

‘I’m on my way there,’ he said.

‘If you haven’t passed the turn-off, let me come with you.’

Saffron Ortley lived forty minutes out of London and en route to Dover. Bish was tempted to lie, say he was long past the turn-off, but his head felt like jelly and lying took effort.

‘Please, Bish. I don’t want you going there alone.’

Three hours later they were sitting on the ferry, sailing towards a nightmare of uncertainty. Saffron, though, had the look of cool practicality that came from years of being a diplomat’s wife. She was the person people noticed when she entered a room, and now, in the ferry lounge, two elderly sisters on their way to visit a niece in Bruges asked her if she’d be a dear and get them a pot of tea. She had already rearranged the seating between them and a couple of backpackers who thought their packs needed a seat of their own. All without a fuss.

‘Who could stomach a beer on a Channel crossing?’ one of the sisters said, watching the activity at the bar where Saffron was buying the teas and shortbread.

Bish could. He could stomach a drink anytime.

Rachel rang just as they were about to drive off the ferry. ‘I spoke to Bee a minute ago,’ she said.

The relief made him dizzy and he rested his head against the steering wheel, waiting for the spinning to stop. He felt his mother’s hand on his.

‘Bee’s okay,’ he told Saffron.

‘She’s pretty shaken, but not hurt.’ Rachel’s voice sounded small. ‘Who’s with you?’

‘Mum,’ he said. ‘So was it Bee’s bus?’

He couldn’t hear her reply. Could hear only her crying, so he figured the answer was yes.

There had been a moment of absolute clarity on the M20, between Maidstone and Ashford: if his daughter was dead Bish would end it all. He’d already identified the body of one of his children. He couldn’t do that twice in his lifetime.

‘I’ll ring you the moment I see her,’ he said. ‘I’m putting Saffron on.’

His mother took the phone and pointed to the other side of the road. ‘Darling, we’re in France now. Hug the right.’

The campsite was thirty minutes’ drive from the port, just outside Boulogne-sur-Mer. It was set within a hundred hectares of wooded land. On a non-heinous day, when a bus carrying teenagers hadn’t been blown up and helicopters weren’t hovering overhead, it would have been a perfect place for quietude. But with no CCTV and no eyewitness on every corner, Bish knew the investigation would be a painstaking one. Halfway down a gravel road that would barely allow the girth of a bus, it already looked like a single-file car park, packed with press vans, police cars, paramedics and desperate local parents. Bish pulled over, knowing it was futile to drive any further.