Jennifer immediately clambered to her feet and ran over to Bailey, shooting her a look of grudging regard.

‘Not bad-going, little sister,’ she murmured.

Jennifer turned round to face Nancy, extended one arm and leisurely shot her the finger.

Nancy’s jaw clenched furiously. ‘You’ll never get out of here alive,’ she growled in her husky smoker’s voice.

‘We’ll see about that,’ muttered Bailey as she began to back away from them, holding the grenade outstretched in front of her.

Together, she and Jennifer edged slowly away from the Molloys, making their way inch by excruciating inch to the concrete stairwell. The shotguns tracked their movements all the way, but no one dared to fire. No one wanted to die.

The two sisters began to descend the stairwell and as soon as the Molloys disappeared from sight, they both turned and rushed down the steps, Bailey leading the way.

Her heart was beating fast now, adrenaline firing through her system, turbo-charging her flight. She knew the Molloys would already be coordinating their pursuit with those outside, hoping to catch them in the middle.

They raced down the rough concrete steps, jumping down two or three at a time, trying not to fall and twist an ankle or break a limb, for that would be truly fatal. Twelve flights later, they reached the bottom of the stairwell.

‘This way!’ said Bailey breathlessly, pulling Jennifer by the arm, tugging her in the direction of the hoarding through which she’d crowbarred a gap little more than ten minutes earlier.

But with a jolt of dismay, she saw they were too late. Already the Molloy thugs who’d been guarding the entrance were running towards them, cutting them off. And it looked like they were holding guns.

‘Shit!’ she cursed.

Bailey turned sharply, heading away from them into the centre of the building site, Jennifer close behind. They stumbled over the muddy, uneven ground, their feet catching in the ruts created by the tyres of the huge vehicles now stationary all around them.

Weaving between Portakabins and huge stacks of metal girders, they fled ever deeper into the industrial gloom. All the while, Bailey kept a firm grip on the grenade in her right hand, fully aware that if she loosened her hold on it for even a moment, then she would blow up both herself and her sister.

Behind them, she could hear the Molloys shouting amongst themselves as they spilled out of the apartment block and fanned out across the building site in pursuit.

Bailey crouched down behind a JCB, pulling Jennifer down with her. Panting hard, she peeked over the top of the bonnet. It looked like there were now at least ten armed men searching for them, with Shane leading the way hefting a sawn-off shotgun.

‘I can’t believe you came for me,’ said Jennifer in contemptuous amazement. ‘That has to be one of the dumbest things anyone’s ever done for me. Why did you even bother? I thought you said I was little more than a common criminal.’