Siobhan was baffled. She had literally never seen anything like it. All cars nowadays were individually smart. They took data and instructions from traffic control systems and navigational satellites, and were able to avoid cars, pedestrians, and other obstacles in their immediate surroundings. Crashes were virtually unheard of, and traffic deaths had dwindled to a minimum. But the scene below was reminiscent of the motorway pileups that had still blighted Britain during her childhood in the 1990s. Was it possible that all the cars’ electronic guidance systems had failed at once?

Light flared, dazzling her. She flinched, raising her hand. When she could see again, she made out a pall of black smoke, rising from somewhere to the south of the river, its origin lost in murky smog. Then a shock wave reached the Society building. The tough old structure shuddered, and the window creaked. She heard a more remote tinkle of glass, the blaring of alarms, and screams.

It had been an explosion, a big one. The cosmologists murmured, grave and apprehensive.

Toby Pitt touched her shoulder. His face had lost all its humor now. “Siobhan. We’ve had a call from the Mayor’s office. They’re asking for you.”

“Me? …” She glanced around, feeling lost. She had no idea what was happening. “The conference—”

“I think everybody will accept a postponement, in the circumstances.”

“How can I get there? If that mess outside is typical—”

He shook his head. “We can videoconference from here. Follow me.”

As she followed his broad-shouldered form out of the City Rooms, she raised her own phone. “Mother?”