It was now or never. If she didn’t act, if she didn’t seize this unexpected opportunity, she might never get another chance.

Selima kept her head down, shuffling along at the back of the line of silent workers, looking for all the world as broken and listless as them.

But inside her heart was racing. She’d long given up hope of freeing herself from her torment, the soul-crushing routine of back-breaking labour and casual violence, but fate had thrown her a lifeline, one last chance to gain her freedom.

She wasn’t sure what the injured woman’s name was – she was a new addition to their ranks and didn’t speak much English – but whoever she was, she had Selima’s undying gratitude.

Their team of a dozen workers, clad in a uniform of drab joggers and tatty face masks, had been trudging back to their transport when the new recruit had suddenly collapsed.

Her legs had gone from underneath her and she must have hit the ground hard, for she appeared to be unconscious, her mouth slack, her eyes rolled back.

It was shocking, unexpected … and it jolted Selima from her torpor.

She’d been following her co-workers in a daze, stumbling towards the open mouth of the van, but the poor woman’s collapse had roused her.

Selima looked at the stricken woman, then up at the awaiting van, a shiver running down her spine.

She’d sat mute and hopeless in the blacked-out interior many times before, but tonight the mouth of the van seemed even more menacing than usual.

Selima had the strong feeling that if she stepped inside again, she might be swallowed up completely, disappearing from the earth as surely as if she had never existed.

The thought stung her, bringing tears to her eyes, the horror of never seeing her children, her beloved husband again, too much to bear.

Somehow she had to resist, somehow she had to find the will to survive .

Now she had her chance. Naz, their chief minder, a pitiless thug with heavy scarring around his unmoving, prosthetic eye, was stooped over the young Syrian, slapping her face with his rough palm.

His charge failed to respond, however, prompting an anxious look at his accomplice, who remained by the van doors, counting the workers in.

Aggravated, but concerned, the associate now hurried over, keen to be away before they were spotted by someone.

This was highly unlikely of course – they were in a scruffy back-alley in the dead of night – but his anxiety persuaded him to drop his guard.

For a moment, the eleven queuing women were unattended, the injured worker occupying both guards’ attention.

The others seemed clueless as to how to respond, their lengthy imprisonment robbing them of all agency, but Selima was not going to let this golden opportunity pass.

She took one step to the left, heading away from the line of human statues.

Then another, moving obviously out of formation now.

She half expected to be yanked back into line, a snub-nosed revolver shoved in her face, but darting an anxious glance in her captors’ direction, Selima saw that the two men were still crouched over their charge.

Speeding up, she padded away, the mouth of a nearby alleyway beckoning.

She had no idea where it led, but she assumed it would spit her out into a street where there would be people, life, perhaps a police officer.

Anything – arrest, incarceration, even deportation – would be better than this.

‘What do you think you’re doing?’

Selima kept walking, breaking into a half-jog, praying that this snarled question was aimed at the ailing woman.

But as she heard her minders scramble to their feet, she knew she’d been spotted.

A quick glance over her shoulder confirmed this, Naz now tearing towards her, his face contorted with murderous rage.

Already he was reaching into his jacket, to pull out what?

An iron bar? A gun? It was too late to slip back in line.

Too late to pretend she’d made a mistake.

A rebellion like this would not be tolerated, her life forfeited, which meant Selima had no choice.

She had to run.