So he arrived in an anonymous BMW in Soho, an area of tight, crowded roads, the cars cruising inches from the elbows of cappuccino-sipping customers of pavement cafes. Most of the population here looked young, sleek, dressed well if sometimes bizarrely; Venus protection had been subsumed into fashion, and the girls in their ponchos looked like butterflies.

The car pulled into Frith Street, just off Soho Square. Henry got out with the holdall full of spare clothes and bathroom stuff that he’d requested on the way down from Edinburgh. His hotel was a neat little converted eighteenth-century house, another corner of Britain that was, no doubt, older than his entire country.

His room turned out to be a box, a typical city centre room, no doubt ruinously expensive, but His Majesty’s Government could worry about that. His escort, a couple of bullshitting squaddies, were booked in the hotel, down the corridor.

He threw his holdall down on the bed, shucked off his filthy clothes, and climbed straight into the shower, which was a modern fitting with a hot and powerful jet.

Ash-grey shit soaked out of his skin, and made little whirlpools at the plug at his feet. Bits of burned Edinburgh, rock just a day old, the youngest rock on the planet.

Drying off, he turned on the TV. All the regular programmes were suspended, save for one channel that was carrying children’s TV — he saw five seconds of it, weird little aliens that bounced around and spoke gibberish, Christ, bring back Sesame Street — and on all the other stations there was, of course, only one story.

Images of Arthur’s Seat, before and after the explosion. Before: waving cultists in their purple pyjamas, upturned faces like daisies, maybe one of them Michael Dundas’s.

And Arthur’s Seat after, a smouldering crater, still pumping out ash and steam.

And all of the people, as volcanologists say, part of the sunset now.

Here was the New Town after the pyroclastic flow, like an image of Hiroshima after the bombing: stumps of buildings, shorn off at little more than knee-level, surrounded by smashed and strewn rubble and covered by a ghostly powder-grey layer of ash, nothing left of the great Georgian design except the rectangular layout of the streets.

There were people already picking through the rubble, some in volcanologists” protective suits, others, heroic, in nothing more than regular emergency gear. The scientists were recording what they could, pyrometers and thermocouples measuring the dwindling heat of the smashed ground. The rescue workers were using microphones and other gear to search, forlornly, for survivors, maybe people who had ridden out the ash storm in cellars. So far, the news guys said, not a one had been found.

Henry could see how the heavy ash cloud, seeking the lowest points to pool like the sluggish liquid it was, had swept like a transient river around the other bony basalt outcrops, Calton Hill and the Castle; in fact most of the structures on those hilltops were still standing. But both plugs were marked, distinctly, by the cancerous grey scars of Moonseed pools. It would only be a matter of time before they went the way of the Seat, and added to the destruction of the area.

And all the time the Moonseed was spreading, chewing up the Earth, disrupted briefly by the destruction it caused, but always returning, stronger and more widespread than ever.

The cameras focused on the human misery, the scenes on the roads and assembly points and Rest Centres, improvised from schools and hospitals and leisure centres, most of them all but overwhelmed. People were crammed into whatever shelter could be found, bereft of their homes and belongings, lucky if they kept their families with them, stripped by the intrusive cameras of the last of their dignity.

It was impossible to believe he was looking at a Western city, Henry thought uneasily.

He needed to talk to Jane.

He used the hotel phone to try the contact number Chief Constable Romano had given him in Edinburgh, a direct line to the Police Casualty Bureau. It took a while to get through even so, and when he did there was no record, on the improvised database the young man on the other end was consulting, of Jane or her family.

But then, looking at the televised chaos of the evacuation, he wondered what percentage of the refugees had finished up on any kind of official record anyhow.

The Brits just weren’t ready for this.

Why should they be? Britain floated like a rocky raft in the stable centre of a tectonic plate. It should have happened to us, he thought. Americans. We’d have been ready.

Up to now, anyhow. In the long term, if the Moonseed could not be limited, no experience with disaster management was going to stave off the bad rain that was coming down on them all. Maybe his instinct to get to the centre of things, to figure out a way to propagate his bad news, was mistaken. Maybe it was all futile anyhow.

He should have stayed with Jane.

He called Blue Ishiguro. He got Blue’s mobile; Blue had evacuated himself, along with Marge Case and the rest of the department.

We are intending to continue our studies, Blue said. We will continue to go back in to the site as long as it remains stable.

“What about McDiarmid? Where the hell is he?”

Your esteemed leader. Nowhere to be seen. The smart money is that he long since decanted himself to London or maybe further afield.

“Asshole,” Henry said.

You never know how far a frog will jump until you punch him.

That got a laugh out of Henry.

Blue remained serious. Henry, we have nothing but bleak hypotheses here. Now that the Moonseed has got into the mantle, as it surely must have —

“Yeah.” Even now it must be breeding down there, in the slushy layers beneath the continents. Building its fat little superstring bombs.

Although we may contain the surface effects—

“Hell, we can’t even do that.”

It is difficult to see what can stop it.

“I know,” Henry said.

We can’t evacuate forever, Blue said. Eventually we will run out of planet.

The light in his window was fading. The end of the day. Eventually we will run out of planet.

Of course it wouldn’t come to that. They’d find some way to combat this thing, or else it would self-limit. But still, maybe somebody should be thinking about extreme contingencies.

Now, what the hell was stirring at the back of his mind?

“Blue, I’ll call you back.”

Henry—

He put the phone down.

He lay on the bed, as the light deepened, and tried to let the thought coalesce, in the recesses of his head.

An official car came to pick him up the next morning. A black Daimler, for Christ’s sake. He sank into soft leather in the back. His escort, one of the squaddies, followed him, looking even more uncomfortable.

A police escort, two outriders, took them at a brisk pace through the London traffic.

They turned off Whitehall into Downing Street, through heavy steel barriers. Henry got out of the car, in front of what was maybe the world’s most famous front door: in fact just a polished black door set in a mundane-looking terrace.

There were press ranked up on the other side of the road, behind a cordon. There was an explosion of flash bulbs, a bank of TV lights that glared despite the brightness of the day.

“Henry!” “Henry Meacher!” “What are you going to tell the Government, Dr Meacher?” “Is Britain doomed?” “This way, Henry!”

A policeman at the door saluted him. “Christ,” said Henry, unnerved. “How did they get my name? You’d think I was the Prez come to call.”

The copper, a grizzled forty-year-old who looked as if he had seen it all, just nodded, face stern and blank.