“Looks like it’s broken. I’ll check it later.”

They stood there for a moment, looking up at the lorry from the driver’s side; the cab was astonishingly intact. They walked round it, and as they reached the near side, they saw the door was open, and a girl was standing on the step. She jumped to the ground.

“You OK?” said Jonathan, and then, “You weren’t in there, were you?”

She stared at them both, her expression totally blank, then shook her head, turned her back on them, and vomited rather neatly onto the road. She was very young, and very pretty, Jonathan noticed; after a moment she walked, slowly but quite steadily, towards the hard shoulder, where she sat down and put her head in her arms.

“Shocked,” said Jonathan, “but she seems OK. Extraordinary.”

“She can’t have been in there, can she? Or climbed up to have a look?”

“God knows. Look-I’m going up into the cab. Make sure the engine’s turned off there. It could explode any moment.”

Oddly, he didn’t feel frightened, wasn’t aware of being brave; just knew it had to be done.

Constable Robbie Macyntyre had been dreading his first big crash. He just didn’t know how he would deal with it. He wasn’t exactly squeamish, and of course they had spelt out to them in training that things like severed limbs and worse were inevitable and shown them DVDs. It wasn’t that; more the thought of people in terrible pain, crying out, begging for help.

The first calls had come in five minutes ago; hundreds more would follow. Already two cars had left the depot, and he was in the third, with his colleague Greg Dixon. Robbie was intensely grateful that this was not Greg’s first big crash, or even his hundred and first. “Been doing this for ten years,” he’d said to Robbie when he joined the unit. “Got pretty bloody used to it. Bloody being the word, if you get my meaning.”

As far as they had been able to establish, the congestion on the road was already severe in both directions.

The main priority now, apart from clearing a way for the emergency services to get through, was to garner information and communicate it to the control room: how many casualties, how many ambulances would be required, whether the fire brigade would be needed to cut people out.

Robbie kept remembering his superintendent’s words: Gridlock on the motorway takes seconds: you’ll have a mile tailback inside a minute.

One of the main problems subsequent to a crash, he’d been told-although it didn’t sound as if it would be today-was rubbernecking. “You can get an incident entirely on one carriageway and the traffic comes to a standstill on the other,” Greg Dixon said. “Just because people slow down, even crash into the car in front at times, just to have a gawp. Good old Joe Public.”

He didn’t take a very rosy view of Joe Public; Robbie was swiftly coming to realise why.

Jonathan slithered down from the lorry’s cab; the Ford driver was still there.

“OK?”

“Yes, the engine was off. Hell of a mess up there. Windscreen’s shattered, blood everywhere. Poor bugger driving it’s not too good, though.”

“I bet he’s not. Is he… alive?”

“Just. Maybe not for long.”

“Should we get him out?”

“Christ, no.” He glanced over at the hard shoulder. “That girl OK?”

“She’s disappeared,” said the man. “She was still sitting on the hard shoulder last time I looked. Nobody with her. But she’s not there now.”

“Wandered down the road, I suppose. She seemed very shocked. Oh, well. She’s the least of our worries, I have to say…”

A man was walking towards them, holding a small boy by the hand; he was crying and saying, “Mummy… Mummy…”

“Is he all right?” Jonathan said.

“He’s all right,” said the man, and he spoke so casually it was as if he was discussing the weather. “His mother’s not, though.”

He nodded in the direction of a large black car behind him; its windscreen was shattered and there was a woman lying on the road; she had clearly come through the windscreen.

“She just undid her belt, just for a second,” the man said, “to give the little fellow a drink. And she… she…”

He shook his head, turned away from them.

“I’m a doctor,” said Jonathan gently. “Would you like me to come and see her?” He knew it would be futile, but it needed to be done. The man nodded. “If you wouldn’t mind.” The man with the broken arm looked after them. “Poor bugger,” he said, “poor, poor bugger.”

Emma had just finished eating a rather dodgy BLT when the news came through: of a major crash on the M4, of a jackknifed lorry, a crushed minibus, road blocked in both directions, almost certain fatalities. And by some grisly coincidence, there was a second accident farther down the road, a continental truck with a blowout had slewed across the exit road of the next junction. Nobody was hurt there, but there was a mass of traffic behind it, and an obvious route for the emergency services to the crash, travelling the wrong way up the motorway, was temporarily, at least, out of the question.

She half ran into A &E and put in the trauma calls, the special unmistakable bleep, summoning people to A &E, removing them from their day-to-day work and rosters; she would need, she reckoned, an orthopaedist, a cardio thoracic surgeon, two general surgeons, two anaesthetists, a general surgical registrar, and ATL-hospital shorthand for advanced trauma and life support. Plus at least ten nurses.

They stood together in A &E. a group of people, some of whom knew one another only slightly, working as they did in totally different departments of the hospital, others who were in daily contact. There was a minute of formalities, of handshaking, name giving.

Alex Pritchard appeared; half an hour earlier he’d waved to her across reception, off on a clear weekend.

“Thought I’d better come back, see if I could be useful.”

Apart from the surgical registrar and Alex, there was just one other properly familiar face: Mark Collins, a young orthopaedic registrar she’d worked with a few months earlier on a ghastly multiple motorbike crash. He had been great then, calm and tireless.

“Hi, Emma. This sounds like a big one. Worse than the bikers, I fear. OK. Who’s going to be team leader?”

That had surprised Emma, on her first big incident. Somehow she’d thought everyone would just know what to do anyway. But it was essential, she had discovered, to establish a chain of control-for order and swift delegation, and to cut through the chaos and any panic; the first thing ambulance crews always asked on arrival was, “Who’s team leader?”

“You, Alex?” she said now to Pritchard.

“OK. All right with everyone? What news, Emma?”

“Well, it’s pretty bad. Jackknifed lorry, trailer on its side, driver trapped, several cars, minibus-three lanes blocked, in both directions, several fatalities. And someone just rang to say people are driving down the hard shoulder in the westward direction, so the road could be impassable pretty soon.”

“Is the driver of the truck alive?”

“So far. Amazingly, there’s a doctor right on the scene. He rang to report that the bloke was completely trapped, steering column embedded in his chest, just about conscious, pulse very weak, but definitely alive-Excuse me.” Her phone had rung-it was the first of the ambulances. “Hi. Yes. We have a full team ready. Good luck.”

Jonathan had turned his attention to the minibus; the driver’s door was jammed shut, but the one at the rear opened fairly easily. There were eight small boys inside, all miraculously unhurt, but the driver was dead, hideously so. He was about to climb in when he heard Abi’s voice: “Jonathan, what can I do?”