She put the Sat Nav on because she couldn’t do it on her own, even though she’d driven this route at least twice a day for the last thirty years.

At the end of the road, turn left…

When was the moment? she thought. When did I make the choice that ended here? Was it when I wanked thinking about Macdowall?

—At the roundabout, take the second exit, Renfield…

Was it when I did a home visit to McKinley on my own? Which one? The first with the doll, or the second with the pen drive? She wasn’t supposed to do home visits to sex offenders on her own, for reasons she now understood, but there was never anyone available to come with her. If she’d waited around till someone could, she’d have been in trouble way before now.

At the roundabout, take the third exit, Renfield…

Small decisions, all of them, but one of them set things off.

In two hundred metres, turn right, Mason Court…

As she turned, she spotted Jimmy McKinley’s bungalow. The front door was open. Paedo and Beast had been spray-painted on the pebbledash and door, and at least one window was broken. He’d fled, obviously. Underground now, with no supervision whatsoever. Mary had made him more dangerous.

—In two hundred metres, turn left, Grange Road…

Thank God she had the meeting in ten minutes: to be in a room with qualified listeners, to be comforted, have things clarified, decisions made. She couldn’t leave the job now, not with Roddie unemployed. She couldn’t take any more sick leave because she was stage four now, probably, which meant something very bad. Her flexitime had been swallowed again, she had no holidays owing, and no money to buy extra leave. She had to fight to stay in this place. She had to find a way to cope. She must not let anything set her off again.

—You have reached your destination.

Mary pulled up outside the office and rummaged for change in her grotty car. There was a parking meter epidemic in Renfield, even though very few residents drove a car – not their own, anyway. She’d tossed her fury to the wind re parking years ago, but it boomeranged now as she scraped a twenty-pence piece from the floor and picked off the brown substance coating it. She had to pay? In this wasteland, near a sewage plant. Where no-one even had a car except the council army that had long occupied the area – the Stasi soldiers who paced the High Street at lunchtime, lanyards swinging from their necks. She counted out two quid in silver, put it in the meter, and opened the boot. Tuna was plentiful – no-one wanted that – but she was running low on baked beans and UHT milk. As usual for the last week or two, she left the boot open, and stuck her laminated PLEASE HELP YOURSELF sign on the number plate.

Mary was vibrating, she was an enormous walking Just Ears. Her son had just been arrested for downloading abusive images of children. Right now, he was handcuffed in the back of a van. To the drivers, he was the scum of the earth. In prison, he’d be abused and beaten. In court tomorrow, men’s rights activists and Renfield Star journalists would jot down details to embellish and spread. Online, he’d be the evil monster we must all watch out for. He’d have to register every year. He wouldn’t be allowed to have his dog. Marty! He wouldn’t be allowed to have Marty. The law firm would sack him. If found guilty, he’d never practise law, or get any kind of job, ever. He wouldn’t be allowed near children and if he went near a woman, social work would put a stop to it. He’d go to groupwork with the likes of Jimmy McKinley, and maybe he’d learn a thing or two, make some pals.

She stopped before the front doors because she couldn’t breathe. ‘I must not think about that. I must not think about that,’ she repeated, definitely out loud, because a skinny client was offering her a cigarette.

He lit it for her.

His kindness, as well as the deep, smoky breathing, calmed her. She had arrived at the right place, the concrete box she’d worked in for thirty years, where chaos was expected and unhappiness the currency, where she was the goody who worked with the baddies, where poverty made her feel rich and despair made her feel blessed, where her colleagues were her mates, her boss her confidante, and where crises always blew over.

Management didn’t know she’d done anything wrong. To her colleagues and bosses, her client had committed suicide, which was a pain in the arse and would involve months of scrutiny on every level, but was nothing unusual. She’d been doxed and trolled, which was shitty, but not her fault. And she’d have to prove she didn’t shag Macdowall, but she reckoned she could do that – maybe using the location device on her laptop or phone, or something, or asking Holly to make a statement. There had to be a way.

As for Jack, Mary needed time to think up a more believable story than the truth. The bosses had dealt with this kind of thing many times. Last year Alice Belmont’s son killed his mate after a drunken game of quoits turned nasty. Alice, a children-and-families social worker, was restricted from all information pertaining to her son, but otherwise she was unscathed. She took the last drag of her cigarette and stubbed it out.

The automatic doors opened. ‘Hi Nel,’ she said to the receptionist.

Nel was on the phone and gave a weak wave.

In the waiting room, there were two Mental Mothers – one shaking, one crying – with their three Kids at Risk.

‘Hey gorgeous!’ Mary said to Kid at Risk One, whose name was either Chloe or Zoe.

‘I have juice,’ Kid at Risk One said, and Mary was excited too. Chloe or Zoe didn’t often get juice.

Beside Mental Mother One was an out-of-place thirty-something man – interpreter, Polish, probably, as the Poles were the only migrants to have willingly settled in the area since 1900. Opposite him, a middle-aged woman grasped her designer bag (divorce, drink driving). An elderly heroin-user rocked on the seat next to her. (All heroin-users were elderly. This one deserved an award for still being alive.) Mary smiled at the Heroin-User, the lowest of the low, or almost. Junkie: an unspeakably dirty word.

Mr Angry in the corner was seething cos he had to come to this fucking place. I hate you, he was saying to Mary with his whole face, and Mary’s whole face was saying: Not as much as I hate you.

And there was a guy in the telephone-box-sized room next to Nel. He’d been put there for safety reasons. Everyone knew this was the equivalent of the naughty step; that he was either a paedophile or a rapist. Rapist, Mary had decided straight away. He almost filled the entire booth and looked rapey as fuck. The glass had fogged up and he’d drawn a love heart on the steamy window, making Kids at Risk One and Three cry.

Jack might end up sitting in this blowhole of a reception, Mary thought. He’d be the one in the kennel, everyone looking in, everyone – even Mr Rapist, Mr Junkie and Mental Mother Two, who had just vomited in the plastic bin – would look at Jack and feel better because they were not the lowest of the low after all.

She pressed her ID against the machine. Minus seventeen hours, it said. She stared at it a long time. Minus seventeen hours. She took the stairs to the first floor.

The hangar-like space was heavy with Monday-ness, which was the saddest day of the social worker’s week. Weekends always failed to deliver, and workers wore the disbelief on their faces all day. I am back here already. This is my life. This is all I do and I hate it.

It was 3.50 p.m. Mary walked past the community service pod, where Keith was enjoying his power on the phone: ‘You got to the food bank, yeah, yeah? If you can get there, Michael, you can get to your unpaid work, see what I’m saying? No, no, let me speak. No, that’s a final warning, Michael.’ She tried to catch Keith’s eye, but didn’t manage. He might talk to Roddie that way, she thought.

Her pod was empty, bar the pile of papers on her chair.

She spotted Lil exiting at the childcare end of the room. Lil was here, thank God. Or had she seen Mary first and pelted? News might well have reached the office about Jack’s arrest. Minnie might have phoned Catherine, who might have messaged Lil. In for four, hold for seven, out for eight. She had too much to fix and must repel the red mist.

The papers on her chair included a new life licence, which Mary scanned. Iain Sanderson, who’d raped and murdered three elderly women in 1987, 1988 and 2007. She had been allocated five court reports: assault, drink driving, drugs, stalking, one for racist prick Simon Gallacher and one for Derek McLaverty (bail act, domestic assault).

She put her head between her legs for a moment, then opened the window to take in some sewage air. A moment later the desire to smash everything in the room subsided a little, and she returned to the complaint against McLaverty.

After returning from the Edinburgh Book Festival, he had turned up at his in-law’s house to see his boys and banged on the door till his ex-wife came outside. He was found guilty of breaching bail, pulling her hair, punching her in the face and throwing a large rock at her back. Whoever allocated the report was blissfully clueless. Mary would ask to have this report reassigned.

If Jack was found guilty, one of her colleagues would get a report request like Derek’s. Lil, maybe. Or Sylvia. Whoever it was would scan the paperwork as Mary just had, see his name and age and crime and think: Agh. Gross. Arsehole.

She also had about thirty telephone messages, many from people she didn’t know or couldn’t remember, and seventy-two emails, none of which looked terrifying at first glance.

She was starting to feel less unsafe.

Catherine wasn’t in her office, which meant the meeting would be downstairs, and that Mary would have to do the walk of shame. She braced herself and made the journey she had made thousands of times, past Sylvia in criminal justice, who’d usually look up to say hi, but didn’t today; past the children-and-families workers who were busy praying Please don’t let me ruin a child today. Please do not let me ruin a child. None of them acknowledged Mary because news had obviously already spread. She was a walking nightmare. Behold Mary, they were all thinking – and never, ever take the mother’s word for it.

Because Mary had ruined a child’s life today. Her own.

She was dizzy when she reached the opposite door, and only made it halfway down the stairs before needing to sit. A moment later, the door behind her banged. Footsteps. Someone was coming.

‘Mary!’

Fuck, it was the green-haired student social worker. Mary didn’t have her headphones, shit. She decided it was best to make a dash.

‘Mary, stop!’ The girl had caught up with her. Her hand was on Mary’s arm. ‘You’re shaky. You’re going to fall over. Stop. Sit for a minute.’

Mary collapsed onto a step and blurted out: ‘There are no programmes of offence-focused work for autistic gamblers. I’d just have to make it up, and it’d take ages, and I don’t want to. I don’t want to help you.’

The student social worker was holding her. How did that happen? ‘I heard about your son. I’m so sorry.’

‘He didn’t—’

‘I know. Of course he didn’t. I know. I believe you. It’s okay. If anyone can get through this, you can. You’re amazing. Here.’ She took Mary’s hand and pulled her upright. ‘Where are you heading? I’ll take you.’

The conference room stank of the power of senior social workers. Catherine, her boss and confidante, sat at the far end of the enormous table, and gave Mary a nervous smile. Beside her was her boss’s boss, Shirley, whose presence made Mary hot and itchy.

She had to hold it together for Jack. ‘Can you give me a moment?’ She concentrated. ‘I’m having a panic attack. Just a moment…’ Four, seven, eight, she repeated three times, even though she didn’t feel much better, then began contemplating the daunting task of lifting her head.

‘Mary? Mary,’ Shirley said. ‘Are you okay?’

The table had morphed into the one at Lowfield, and Jack was surrounded by officers and social workers:

You will not. You may not. You must not. Without the prior permission of your supervising officer.

‘Mary!’ Shirley was starting to sound mean. This often happened with Shirley.

Was that the red mist rising? It felt red. But it felt more ominous than mist.

‘I understand you’ve been going through, well, a lot, but this is a very serious situation, Mary, and we felt we really shouldn’t postpone.’

Shirley kept talking, but Mary couldn’t hear for the terrible snippets invading, making her dizzy again:

I made an excellent decision today. I beat up a paedophile.

She imagined Derek McLaverty kicking Jack in his cell, smashing her bleeding boy’s skull.

You’re the blast and I’m just another of your fucking ripples!

She imagined Jack having dinner in D hall, chatting away with Jimmy McKinley and Robert the Rapist.

‘I must not think about that,’ Mary said, which made Shirley stop talking and Catherine look up.

Her calves were itchy and she had to scratch.

‘As I was saying…’ Shirley swept a piece of paper across the table for Mary to peruse. It was filled with numbers, which began to blur, swirl and redden. ‘The dates we’ve highlighted,’ Shirley said, ‘are the days you arrived outwith core hours or left within core hours. Thirty-three times since Christmas, Mary.’

She finally managed to lift her whirling, leaden head. She looked at the spreadsheet, then at her boss, then at her boss’s boss, then at her boss again, and said: ‘This meeting is about flexitime?’