They followed him to the structure, which proved to be the top of a spiral staircase.

“What’s to stop the people down there from coming up here?” Sadhvi Raghavendra asked.

“Superstitious dread,” Trounce answered. “The maxim ‘know your place’ has been drummed into them for nigh on a century.”

“Will we attract attention by going down?”

“We’re Uppers. We can go anywhere.” He checked that their faces were all sufficiently shadowed by the hoods, gave a nod of satisfaction, and started down the metal stairs. Burton followed, Raghavendra was next, then Wells, and lastly, Swinburne.

The stairwell—a plain metal tube—was lit by a strip of light that spiralled down anticlockwise just above the handrail to their right. The illumination served only to accentuate the narrowness of the cylinder, and, as they descended, Burton’s respiration became increasingly laboured, his claustrophobia gripping him like a vice.

Their footsteps clanged and echoed.

After five minutes, an orange radiance began to swell from below.

“Is the air getting thicker?” Burton mumbled.

“Actually, yes,” Trounce said. “The Underground is hotter, made humid by steam-powered vehicles, and is pretty much a soup of nanomechs.”

“That do what?”

“That keep the Lowlies placid.”

They suddenly emerged from the tube into an open space. As they continued down the steps, Burton and his fellow chrononauts looked around in amazement. They were in Montagu Place, not far from the corner of Gloucester Place, but aside from the configuration of the roads the area was completely unrecognisable. Where Burton’s house had once stood, there was now a row of derelict—but obviously inhabited—two-storey buildings. Toward Gloucester Place, and across it, visible along Dorset Street, much larger tenement buildings huddled. They were ill-built ramshackle affairs, mostly of wood, with upper storeys that overhung the streets. They were very similar to the old “rookeries” that had once existed in the East End, reflecting the same dire poverty and hellish conditions that had made of the Cauldron such a crime- and disease-ridden district.

In stark contrast to the overground, the streets here were densely populated. Slow-moving crowds were jammed to either side of a band of clanking, growling, hissing, chugging, popping, grinding, clattering traffic. The vehicles were more primitive than those of Burton’s age, for the most part comprised of leaking boilers, smoking furnaces, chopping crankshafts, wobbling drive bands, and belching funnels. Some were pulled by horses or donkeys or, unnervingly, by gigantic dogs. That such methods of transport existed contemporaneously with the saucer-like fliers of upper London was extraordinary.

From all these contraptions, steam billowed into the air, making the atmosphere, which reeked of sweat and filth and fossil fuels, so foggy that the far ends of Montagu Place and Dorset Street were lost in the haze.

Hanging high over the thoroughfares, suspended with no visible means of support, a multitude of large flat panels glowed with letters and disturbing images. The closest, right next to the spiral staircase, portrayed a ferocious and Brobdingnagian slant-eyed panda rampaging across a city, crushing towers beneath its clawed feet, and with hundreds of tiny people dribbling from the corners of its snarling, fanged and blood-wetted mouth. “ONLY YOU CAN SAVE THE UNITED REPUBLICS OF EURASIA FROM ITS OWN BARBARISM!” the floating placard urged.

Farther along Montagu Place, another showed horned demons holding up a “monthly report” and laughing at its contents, which read, “MURDERED: BABIES . . . 2,019; CHILDREN . . . 3,345; WOMEN . . . 12,367; NONCOMBATANTS . . . 67,832. A GOOD MONTH’S BUSINESS FOR THE U.S.A.! STOP THIS HORROR!”

Over the junction with Gloucester Place, a third panel showed a man facing a Chinese firing squad. Behind him, bodies were piled so high they disappeared from view. “SERVE THE EMPIRE. MAINTAIN OUR CIVILISATION. RESIST SOCIALISM. WE ARE SUPERIOR.”

Others panels read, “ONLY ANGLO-SAXON ENLIGHTENMENT CAN SAVE THE WORLD!” and “THE HUMAN SPECIES DEPENDS ON YOUR LABOURS!” and “MUST WE ENDURE SUCH BARBARISM ON OUR DOORSTEP?” and “SOCIALISM CAUSES SPIRITUAL DECAY!”

Higher even than this floating propaganda, curving out and up from the many massive supports of the upper world’s towers, red brick ceilings arched, enclosing everything, so that the London Underground resembled a humungous series of groin vaults, lit only by the gas lamps that lined the thoroughfares and the watery illumination that leaked from many windows. At the peak of each of the arched sections, fitted into dark holes, enormous fans were spinning, sucking out sufficient pollution to render the air breathable, but not enough to adequately clear it.

The whole domain was half sunk in shadow. It was filled with dark corners and fleeting movements; a place of furtive and crafty activities; of things caught by the corner of the eye but gone when looked at square on.

The chrononauts descended down from the ceiling, turning around and around on the spiral staircase, gazing in horror first at sagging rooftops upon which occasional scuttlings could be glimpsed, as if small burglars were fleeing from those who might bear witness, then into upper-storey windows that opened onto bare rooms in which figures lay starving or drunk or exhausted or dead.

Finally, they reached the pavement, where Burton stumbled and was caught by Trounce, who murmured, “All right?”

“Yes,” Burton said. “Bismillah, William, have you brought us to Hell?”

“I’m afraid I have.”

The passing crowd recoiled from them, giving them a wide berth, for the chrononauts were obviously Uppers and thus better, thus to be respected, thus to be feared.

“Oh my God!” Sadhvi whispered.

The people weren’t people. They were less human even than the freakish pedestrians they’d seen in 2130. Shambling past, some were tall and attenuated; others short and bulbous, or bulky like boulders, or small, wispy and wraith-like, or multi-limbed, or half animal, or amoebic as if lacking skeletal structure, or padding along on all fours, or winged, or covered from head to foot in matted hair, or just so thoroughly grotesque that the senses could hardly make sense of them. Many were naked. More were dressed in rags. Most were in Army or Navy uniforms. Their language was the same rough variety of English that Burton knew from the shadier districts of his own London, though quite a few simply grunted or whined or barked or mewled.

The king’s agent turned his eyes to Trounce and they were wide with horror.

“Genetic manipulation continues,” the Cannibal said. “It’s uncontrolled. Follow me. Stay close.”

They began to move toward Gloucester Place.

Suddenly, blaring like a foghorn above the din of the traffic and clamour of voices, there came a thunderous bellowing. “Hot taters! Hot taters! Hot taters! Freshly baked for ’em what wants ’em!”

Burton peered ahead and saw, squatting on the corner, a short bulbous form in baggy garments with a flat cap upon its broad head. The creature’s face projected in a peculiar manner, thrusting forward and flat like a frog’s, with a mouth so wide that it touched the tiny lobeless ears to either side. Was it human? It appeared little more than a blob, with no visible legs or identifiable skeletal structure, and pudgy, apparently boneless arms.

The man—if it could be so classified—suddenly expanded his neck, throat and cheeks, puffing them out tremendously, like a balloon, so that he even more resembled a bullfrog, and opened that phenomenal mouth to once again blast, “Hot taters! Hot taters! Hot taters! Freshly baked for ’em what wants ’em!”

The chrononauts, their ears ringing, came abreast of him, and Burton clutched at Trounce’s arm. “Wait!”

“Don’t—” Trounce began, but it was too late.