Two hundred yards down Sloane Street the tunnel ended in a short flight of steps into a small fortified basement below one of the office blocks. This had recently been used as a temporary first-aid post. Two or three cubicles stood against one wall, behind a boiler. There was a tin desk littered with forms and empty dried-milk cartons.

Crossing the basement, he kicked back a door into the garbagedisposal unit and climbed another staircase into a fortified passageway, where pit props were placed at two-yard intervals. This branched left and right when it reached Lowndes Square. The lefthand section ended abruptly in a heap of rubble where one of the older houses had collapsed into the road. The other ran in the direction of the apartment house, and Maitland climbed through a breach in the wall into the basement garage of the Pakistan Embassy.

In the ramp outside, a long black Cadillac limousine sagged back on a broken rear axle, tires flat, windows shattered, a collection of half-packed suitcases abandoned by the open trunk. Protecting his face from the stones and tiles ricocheting between the high walls, Maitland dived through into the service doorway of the apartment house.

All the apartments had been abandoned, and air whirled around the stairway, changing its direction every few seconds, driving clouds of dust and rubble up and down the steps.

Maitland pulled himself up to the sixth floor and looked into the elevator. A small leather armchair stood inside it, two dirty cushions and a screwed-up blanket revealing the outline of some small figure.

Maitland raced up the next three floors to his own apartment, pushed back the door. The hall was in darkness; air swirled through from the lounge, dragging at the litter of old newspapers and magazines. He ran through, steadying himself as he reached the door. The French windows had been torn out and the steel frames quivered as the wind rushed past the end of the building, an enormous turbulent vortex bursting explosively around the ragged stonework. The outside balcony had been ripped off and all the furniture in the room had been sucked out by the vortex and carried away over the roof of the Embassy below.

For a moment he felt that he was standing over the propellors of some gigantic aircraft carrier, gazing out at the writhing wake as the vessel plunged through boiling seas, shielded from the sky by the overhanging flight deck. He was looking westward across the city, the storm-driven rooftops stretching to the horizon like huge ragged waves, obscured by a spray of dust and grit.

"Quite a view, isn't it, Donald?" he heard someone say quietly at his shoulder. He turned to see Susan in the doorway behind him.

"Susan! What are you doing here?" He reached out to her. "Get your things together and come down to the Underground Station. Everyone's sheltering there."

Susan shook her head and stepped past him into the lounge, swaying as the wind caught her. Her hair clung in a matted net around her face, gray with dust and dirt. She still wore the cocktail dress he had last seen her in. The full skirt was torn and stained, the net underskirt trailing at her heels. One of the shoulder straps had gone and the front of the dress hung down loosely, revealing her scratched dirty skin.

He caught her as she rode a gust of air that swept out through the balcony, pulled her against himself.

"Susan, for God's sake, what are you playing at? This is no time for putting on an act."

She leaned against him, smiling wanly. "I'm not, Donald," she said mildly, "believe me. I just like to watch the wind. The whole of London 's starting to fall down. Soon it'll all be blown away, Peter and you and everybody."

She looked tired and hungry. Maitland wondered whether she had eaten. Perhaps the porter had bartered a little food for a decanter of whiskey, tried to keep her going.

Maitland put his arm around her shoulders, began to draw her into the corridor. "Come on, darling. This whole building will be coming down too in a few hours. You've got to get out of here. The Underground's the only place."

She twisted away from him, revealing a sudden unexpected strength.

"Not for me, Donald," she said evenly, stepping backward into the lounge. "You go, if you want to. I'm staying here." When he reached out to her again she stepped back quickly, only nine or ten feet from the inferno raging outside the balcony, and poised there, her hair swept back off her head.

When he hesitated, she glanced at him pityingly for a moment, then turned and looked over the rooftops. "I've been frightened for too long, Donald. Of Daddy, and you and myself. Now I'm not any longer. You go and dig a hole in the ground somewhere if you want to-"

Her eyes were away from him and Maitland dived forward and seized her arm. Clenching her teeth, she kicked out at him, her slim body uncoiling like a frantic spring. They struggled silently, then Susan wrenched away and stepped back.

"Susan!" Maitland shouted at her. For a moment she stared wildly at him, then moved away. She was only a few feet from the open window. Suddenly the wind caught her. Before he could move it whirled her back off her feet against the door frame; then spun her head over heels into the open air.

Down on his knees, Maitland saw her for an instant, catapulted through the updraught rising from the street, bounce off the roof of the Embassy building and then spin away like a smashed doll into the maze of rooftops beyond. A few feet from him the air pounded at the door frame, ripping away the masonry from the exposed edge.

For five minutes he lay on the floor, head pressed to the dull parquet, the pain and violence of Susan's death stunning his mind. Then, slowly, he pulled himself backward to the door and got to his feet.

The strength of the wind had increased significantly as he retraced his steps through the Pakistan Embassy and along the tunnel to the first-aid post. Somewhere the system of emergency tunnels had been badly breached. As he stepped through the aid post something struck the ceiling above his head, splitting the concrete and sending down a shower of dust. The building began to quiver restlessly, indicating that the roof had been breached. Soon heavy sections of masonry would come toppling through the floors, knock out the central transverse supports and allow the wind to push the walls in like cardboard hoardings.

Maitland climbed into the Sloane Street tunnel. A hundred yards away a single lamp flickered dismally, illuminating the narrow corridor of leaking sandbags, the moisture exuded from the wet cement making it resemble an abandoned sewer. Head down, he hurried along to the station entrance.

He ran down the steps, then pitched forward on his knees, banging his head against the far wall. Picking up his torch, he shone it around the floor, feeling for the steps with his hands.

Halfway down the staircase, heavy steel shutters had been sealed into place, an immovable lid of three-inch plate that cut him off from the sanctuary below.

Trying not to lose his self-control, he climbed out of the staircase and re-entered the tunnel. He switched the torch off to conserve the battery and groped along the walls, his only hope to get out of the tunnel before it collapsed and find a deep basement in one of the buildings off the street that would remain intact when its upper floors gave way.

Above him, apparently far away to the left, a dim rumbling had started. He stopped and waited as it grew nearer, flicking on the torch. Then, ten yards away, in a cataract of dust and noise, an enormous section of masonry plunged straight through the roof of the tunnel, letting in a tornado of exploding brickwork that drove Maitland backward off his feet. As he pulled himself upright the entire roof of the tunnel bulged inward, then collapsed in a vast avalanche of debris that poured in around him, shutting out the light that had burst through the first aperture.