They lay gasping on the bank, clearing the gas from their lungs, but their limbs still heavy as if they had just woken from a deep sleep.

‘Come on, movement’ll clear it quicker.’

Sliding down the bank, they ended up to their knees in water choked with sickly yellow silkweed, then waded along the V-shaped dyke towards the pipe and ducked inside it. The massive crump of an explosion resounded, and a shockwave sent them staggering. Glancing back, Saul saw an enforcer, his clothing afire, slam into one bank of the dyke and roll down it, sizzling in the water and thrashing about, seemingly unable to put out the flames. His screams pursued them into the darkness.

Hannah knew something about the illegal hospitals Saul had mentioned – she had learned about them from the kind of people supplied for her experimental work. He had originally planned on heading for such a hospital, but as they stepped out of the end of the pipe, and a mobile readergun stepped down into the dyke ahead of them, it seemed they weren’t going to get much further.

The incredible unfairness of it suddenly raged up inside her. ‘Fuck you!’ she shouted, and opened fire, but the kick of her gun put her aim well off, the bullets cutting clods out of the dyke’s lip, some distance above the advancing robot. She then threw herself in one direction, while Saul took the other.

Like a harvestman spider, two metres across and fashioned of wrought iron, it crab-walked and slid down the bank, the sharp tips of its extended legs slicing through the mud. As Hannah lay there expecting to die, she noticed how fast Saul moved. Already he was up in a squat on the bank, swinging his weapon round to target the thing, but then he hesitated.

‘Shoot it!’ she yelled, trying to pull her own weapon out from underneath her.

‘Those attacking us would have taken all the readerguns offline, to prevent them shooting their own soldiers or, worse still,’ he glanced her way, ‘killing you.’ He pointed to the robot. ‘If this thing was back to running its usual program, we’d have been dead less than a second after it spotted us.’

Hannah now managed to get her weapon aimed at the thing, but didn’t open fire. She just stared, taking in its details and wondering how Saul managed to show so little fear. The robot’s main body was a squat upright bullet of metal painted in earthy camouflage patterns, a sensory band under clear glass encircled its circumference. The barrel of its gun protruded like a proboscis, while depending underneath its body, like a prolapsed bowel, hung its magazine and power supply.

‘It might have been reprogrammed just to capture us alive,’ he said speculatively.