Looking back, she saw the reddish outline of his head pop up over the wall.

He didn’t fire – which confused her. Until he withdrew, and she heard a fumbling and clicking as he replaced his latest empty magazine. Then she hit the chipboard headlong, crashing through it with an impact so massive that she literally saw lights in front of her eyes. Dazed and disoriented, she toppled over, landing on all fours, and crawling away from the open doorway at an angle. When she glanced back through the narrow gap this afforded her, she saw him reappear at the wall and level his weapon – and a blinding staccato volley exploded towards her.

Only the fact that she was on hands and knees saved her, the hail of lead peppering the wall above her head, knocking out chunks of plaster and pipework, showering her with brick dust.

Yelping like the animal she felt she was imitating, she waddled across the kitchen floor and into the main hall, where she jumped to her feet and ran. Only to skid to a halt, as the poor light spilling in from the kitchen showed riveted steel instead of a front door.

She heard an impact as he alighted in the yard.

Staring back through the kitchen, she saw him. He’d landed badly, by the looks of it on one knee. He struggled to get up, but still managed to lurch in through the shattered kitchen door.

Lucy went left, barging into what had once been the living room. Though exceedingly dark thanks to the sheet steel covering the window, enough light leaked in to show that finally there was nowhere else to run. She turned helplessly, her eyes only adjusting enough so that she could see how empty the room was; it was featureless save for a faux-marble mantelpiece above the maw of a fireplace. Outside, his footsteps came down the hall.

They were clumsy now, awkward. He grunted with pain and effort. He’d hurt himself and was clearly exhausted. But he still had the gun.

Lucy scampered to the fireplace, the darkest point in the room, squatted down and backed into it, crushing her knees against her chest, wrapping her arms around them to make herself as small and insignificant as she could.

And he came in, puffing, gasping, clouds of breath hanging around him. He limped into the middle of the room, so close that she could smell the rankness of his sweat. But now he seemed puzzled. Perhaps, yet again, that mask, which had to be sopping wet, had prevented him spotting her straight away. He dropped the sub-machine gun to his hip; it swung there from its leather strap. Fabric rustled. Perhaps he was digging into a pocket, looking for a torch or phone. Either way, Lucy realised, it was now or never.