Moving on.

The Nene's old course was a serpentine semi-liquid desert, three hundred and fifty metres wide, flat and featureless. All the embankment buildings had been pulverised by the febrile floodwater, their debris sucked away by the inexorable vortices generated by the clash between currents of salt water and fresh water. Since then the eternal mud had oozed back, a great leveller.

Wisbech used to have a bustling port, the river lined by ugly warehouses and towering cranes. Greg had no way of telling where the iron titans had once stood.

Both hovercraft picked up speed on the flat. The heat pressed down, magnified by still, heavy air. Even the gulls abandoned the chase.

Greg received a pernicious impression of waiting depth. He was eager to reach the other side.

Their destination was becoming apparent straight ahead, on the other side of the old river course. The most prominent building there was. An old brick mill tower, slightly tapering, stained almost completely black with age.

Greg didn't understand how it could've possibly survived until they arrived at its base, riding noisily across the buckled corrugated roof of a petrol station which was elevated half a metre above the mud. The tower had been built on the summit of a raised stony mound. While chaos and ruin had boiled all around, it had remained aloof and untouched.

Tufts of tough Bermuda grass grew around its base; there was a good two metres of hard-packed earth between the bricks and the mud. The blades in front of the door were trampled down.

Kendric's hovercraft beached itself on the left of the door, Greg's drew up on the right. The pilot kept going until the bow was bumping the filthy brick, then killed the lift.

The tower door opened and a man came out. He was fortyish, dressed in a fawn sweatshirt and olive-green Wranglers; his shoes were black leather, polished to a sergeant major's shine. A brown belt holster held a Browning 9mm automatic.

Kendric and Hermione alighted from their hovercraft. Greg was hauled to his feet beside Gabriel. The man from the tower took in the fresh crimson splash down his shirt, the way he kept swaying from side to side.

"You were told: intact," he said to Kendric. There was no deference shown. Kendric seemed to be among equals at last.

"He can walk, he can talk," Kendric retorted indifferently, and marched off into the tower.

"Un-cuff them," said the man, "and get them upstairs. He's waiting."

The crewmen began deflating the hovercraft. Mark unlocked the cuffs and waved them into the tower.

Resignation had settled in long ago. Greg stepped across the door, shuffling like one of the undead, shamed and impotent.

The basement was bare, brick walls and concrete floor, a smack of dampness in the air, but not as much as there should've been. He spotted a bright conditioning duct disappearing into the rude wooden plank ceiling. A deflated hovercraft of the same kind they'd arrived in sat in the middle of the floor. There was a cast-iron staircase opposite the door.

"Up," said Mark.

Shiny black shoes were already vanishing through the hole in the ceiling.

The first floor was also one big room, appreciably drier, used for storing crates of food. There were quite a few Harrods hampers stacked beside a small grey metal desk.

The second floor was a living room, carpeted in a thick steel-blue soft pile. Its furniture was modern, matching timber-framed leather chairs and settee, a low ceramic coffee-table, and rose-teak executive desk with a recessed Olivetti terminal.

Cupboards and a glass-fronted drinks cabinet were fixed to the wall, purpose-built, they fitted the shallow incline perfectly. Light shone through a single frosted glass window halfway up the wall. The brickwork had been left uncovered, scrubbed clean.

The dumpy woman who'd accompanied Greg on the hovercraft was waiting at the top of the stairs. Which was impossible, because she was following him up. Had to be twins.

But that revelation was blown straight out of his mind by the next person he saw. Kendric was talking earnestly to Leopold Armstrong. And Greg knew he'd finally met the person who'd organised the blitz on Philip Evans's core.

England's ex-president was fifty-seven, but still trim and fit; his meaty face had a few more lines than Greg remembered, his mop of neatly cut silver hair was combed back tidily. He wore a simple Shetland cardigan over an open-neck cotton shirt. So ordinary. Almost homely.

Greg had thought he was beyond any further surprises, but he just stood and gawked until Gabriel bumped into his back, and her curse was sliced off in mid-flow as she caught sight of Armstrong.

He looked both of them over, taking his time. The tip of his tongue moistened his lips. Greg resisted the ridiculous urge to straighten his rumpled dinner jacket.

Mark clattered up the stairs behind them, and hustled them forward. The little living room was beginning to get crowded. Hermione had stretched out in one of the two leather chairs, feigning lethargy. In addition to the man who'd met them outside there was another obvious hardliner hovering around Armstrong, just waiting for Greg to try something.

"Sit him down, Neville," he said. "Before he falls."

The man who'd met them outside the tower stabbed his forefinger at the settee, and Greg collapsed into it gratefully. Gabriel joined him after a second thrust.

His name had given Greg the key, placing the face; astonishing the trivia a mind can hold. Neville Turner: junior Home Office minister in the PSP government, second-in-command of the People's Constables, one of the many shadow figures orbiting Armstrong's periphery.

Armstrong now held up Greg's Trinities card, a prosecuting counsel with a bloodstained, fingerprinted knife.

"You're a Mindstar veteran," he said. "What on Earth are you doing consorting with scum like this?"

He was setting the tone, speaking normally, no threats, no gloating dominance charades. The ex-president was concerned only with facts, reality; he didn't possess time to waste on life's inessentials.

"Only a total paranoid would be frightened of ghosts," Greg said.

The Trinities card was pocketed. "You mean Philip Evans?" Armstrong asked. "I admit the potential of that fancy NN core of his alarms me. He was remarkable when he only had a human brain. A giga-conductor with a transcendent Evans masterminding its marketing strategy would be a definite setback for me. He's so depressingly efficient at that sort of thing. A clever man. Pity we have opposing political viewpoints. But that's life."

"However, the conflict between Evans and me goes much deeper than that, as I'm sure you're aware."

Greg stared at him dumbly.

"Good Lord, he never told you, did he? Think on it, Mr. Mandel. You've seen Event Horizon's Prowlers at work, I believe?"

"Yes," No ultra-hush there, he wasn't giving anything away.

"Military hardware, Mr. Mandel. Good-quality American military hardware, as provided by that vicious profiteering little arms merchant, Horace Jepson."

Greg started. And Leopold Armstrong caught it. "Didn't you know? Oh yes, Mr. Mandel, Jepson is a US government convenience. He sells to their allies, discreetly, mark you, and in return their IRS overlooks Globecast's somewhat irregular tax returns." He shook his head. "I don't know what all the fuss about you is. You're not half as good as everyone says. But then Mindstar never did fulfil its promise, did it?"

"You were worried enough, I remember," Greg said. "You and your People's Constables. Never had much joy catching us, though, did you?"

Armstrong pursed his lips. "Quite. Well, now you have the facts, make the connection."

Greg read the anger in his face, sharp-focused determination, riding him hard. Armstrong was vengeance seeking, said his native intuition, a strong clear message. "My God," he said wonderingly. "Philip Evans blew up Downing Street."