Revenge fantasies are like warts. You don’t choose them; you hate them, and you pick at them to make them go away – but you’d miss the picking if they did. Mary had been picking hers since 10.00 a.m.

How could she not look online? How can jurors not look? Everyone always looks.

She held out till 10.00, which was a good few hours after her trip to Pollok Park. She was proud of herself, and tipsy again, but what else was there to do but drink and sing and have a bath and go online?

She only looked for a few seconds, but it was long enough. Blogs and tweets and posts and messages had divided the problem of Mary into parts: feminist, wife, mother, social worker. Crazy rants, but everyone seemed to agree on one thing – Mary was bad at all of the above. Derek McLaverty was doing an excellent job of destroying her from his cell. She imagined him inside, posting from his illegal phone, recruiting vulnerable men in AA meetings – maybe even Roddie. He’d already managed with Jack, after all.

She deactivated her Facebook account and closed her email address. She ripped the SIM from her personal mobile, stomped on it and threw it out the kitchen window. She put her laptop in the drawer under her bed, cut the power cord and threw it away. She grabbed her work satchel and tossed her diary on the fire. She ripped up her interview notes and watched them burn: Goodbye Bradley the Perv. Farewell Simon the Racist. Ta-ta Sad Jamie – hope you get the right meds. Ciao Jason the Stalker, Robert the Rapist, Kieran the Homophobe, Sam the Schizophrenic, John Paul the Ned.

For some reason, she couldn’t ditch her work-issue Blackberry, nor burn John Paul the Ned. She’d miss the likes of him. She’d miss asking questions she’d never have the gall to ask her son. She’d miss getting answers.

Mary was desperate to hear Jack’s voice, but she was terrified what it might sound like. It might sound like a man who wasn’t on her side.

She was howling over family photo albums, which Jack had spent weeks organising last summer. (She paid him eight pounds an hour.) There was one for every three years of his life. No-one would know how scared Mary was when she brought him home, not by the pictures in album one anyway. She looked happy and confident feeding him in bed, kissing his head. There was a hint of her worries in the book on the bedside table: How to Bring up Boys, but you’d have to zoom in to know that. Mary didn’t let on how terrified she was of getting it wrong.

Aw, there was Jack in bed, age about seven, his dad sitting beside him, telling him ‘facts’, as he did every night for years. As a result of this ritual, Jack could now win any quiz in town. While the delivery changed, Roddie and Jack had continued swapping facts ever since. The two of them never stopped talking. Arguing. When Mary tried to join in, she regretted it. She knew nothing about Catalonia or utilitarianism.

In the sixth album, Jack was making a Malaysian banquet for Christmas dinner. Perhaps wrongly, she had viewed his love of cooking as a sign that she had got it right.

Jack might not be on her side anymore. He might hate her. He might be roaring that his mother ruined him, that it was his mother’s fault; she was the reason.

How could that be?

She began picking at her wart.

The key’s under the mat, Mary imagined. I tip-toe in, download the pen drive onto McLaverty’s laptop and leave.

The key’s under the mat. I am wearing a trench coat. I walk in, download the pen drive, and leave.

The key’s not under the mat. I kick the door in with my River Island boot. They’ve found their place with the trench coat. Always knew they would. I walk in, download the pen drive, leave the door snubbed open and exit. Later that night, I don a disguise, walk somewhere random and make an anonymous call to the police with the disposable mobile I’ve bought. The husky voice I use totally works with the outfit. I throw the mobile away and head home, smiling, because I have stopped Derek McLaverty. In bed I imagine Derek McLaverty being escorted to the sex-offender’s unit in Lowfield. He is the lowest of the low. A work squad passes in the quadrangle, and someone calls him a beast, another guy spits on him. One day soon, a rapist or a wife-beater will kick the shit out of him to gain status, as advised by Liam Macdowall in his book Cuck. When he gets out, someone like me will stop him from seeing his kids, going to the pool, having a dog, getting a job, taking a holiday, being online: you must not, you must not; you will not, you will not. Someone like me will approve his ground-floor unfurnished flat on a ghost estate ruled by vigilantes, and someone like me will spring visits on him to check how often he wanks and what he thinks about when he comes. He’ll be forced to do groupwork with the other registered sex offenders, and even those guys will hate him; even the guy who raped his granddaughter will feel superior because McLaverty’s a Denier and everyone hates a Denier.

The key’s not under the mat. I use a paperclip to unpick the lock because I am very good at that, but the neighbour hears me and calls the police. The police officer is called Callum Hendrick. He has strong arms and is checking out at my breasts…

…Three minutes later…

The key’s not under the mat, and I do not know for certain how to download a pen drive onto a MacBook or how a MacBook works even.

Intrusive thoughts.

Mary phoned a taxi. She needed to see her husband.

By the time she was inside the rotating glass doors of Lowfield, she felt certain she’d pass as sober in reception. (She wouldn’t have a lengthy driveway ago.)

‘Hey Davie.’ Davie had been an officer for more than thirty years. He was one of the gooduns in Mary’s opinion, but in Mary’s opinion he was also a prick.

‘Which bad boy brings you here on a Sunday morning?’ he said. ‘Shouldn’t you be at St Patrick’s?’

‘You know me, Davie boy, I’d rather go to a mass shooting than to Mass.’ Mary had decided halfway up the drive that she wanted to see Roddie in agent’s, where they’d have their own room to talk; where there’d be no prisoners eyeing them. To ensure this, she needed to pretend her husband was a client. ‘Um it’s Roderick Lawson. He’s on remand.’

Davie checked his antiquated paperwork. ‘You didn’t book this, Mary?’

‘Did I not? Oh my God, it’s the menopause.’ Mary loved telling men ovary-related stories. ‘I keep forgetting things, losing things. You watching the Winter Olympics?’ She changed the subject.

‘Aye with the grandweans, the curling anyway.’ Davie’s tone indicated that he either hated curling and his grandkids, or that he was from Fife.

‘Did you see the paired figure skating? German, whatshername. Wow. The bladder control. There’d be a wet patch on my fanny every twirl.’

Davie had gone pale and was phoning the remand hall. ‘Roderick Lawson. Can you bring him over immediately? It’s his social worker.’

After she was scanned, Mary put her shoes and belt back on and took a seat in the waiting area. She’d been in this halfway room on hundreds of occasions and always used the time to read records, case notes, and any previous reports, so she knew the score before she met the guy, unless he was a first-timer like Roddie. If she was doing Roddie’s court report, she’d have to start from scratch. The ones she started from scratch were always the most satisfying.

At last the door opened, but the wrong door. It was Davie from the foyer area, which was almost the real world. He looked mad.

‘Roderick Lawson is your husband…’

Mary gasped at the revelation. ‘Fucking menopause.’

A few minutes later, Mary was sitting in the governor’s office. Luckily, Karen was on duty.

When she came in, she closed the door and gave Mary a huge hug. ‘Week from hell, eh?’

‘It’s certainly in the top three,’ said Mary. ‘How’s Roddie, is he okay? Can you check he’s got his OCD meds? Paroxetine, fifty milligrams, once a day.’

‘I already checked, and don’t worry, he has. We’re kinda thorough about that right now.’ Karen handed Mary a tissue. ‘Your mascara’s running.’

She was drenched. When she wiped her face, the tissue turned into a rainbow of wet, stale makeup. She sighed – imagine having spare energy to fix her face. ‘He’s nowhere near McLaverty, is he?’

‘Same hall I’m afraid, but no contact.’ K poured a glass of water, put a Berocca in it, and handed it to Mary.

‘Can you keep it that way?’

‘I’ll do my best. Drink it.’

Mary downed the vitamins as directed. ‘I’m a bad feminist.’

‘Ha, join the club,’ Karen said. ‘I watched Tess again last night. Nastassja Kinski fix. Can’t help myself. The guy makes great films. Should we run away to Goa, Mair? Get away from all this toxic bullshit?’

‘Goa. The tickets are on me. I think Lil hates me. I haven’t heard from her.’

K began removing and reapplying Mary’s makeup. ‘That’s because her own me-too disclosure was a really big thing, if you remember. You need to think more than you drink.’

‘I know, I know.’

‘Why would you want to help them weaponise it, for fuck’s sake?’

‘I don’t! I didn’t mean to.’

‘Apologise to Lil, and quit stand-up, obviously. You’re about as funny as a crèche in D Hall.’ K checked Mary over, then dabbed some water on her hair in order to flatten a stray lump. ‘Listen, Roddie doesn’t want to see you.’

‘What? Why? Ouch.’ K was yanking her hair; it wouldn’t stay put.

‘Because they pulled out of the deal. He’s very upset. Ah, there.’

Phew, the makeover was over. ‘What deal?’ All sorts of scenarios raced through Mary’s head, most of them court-related and ending in a lengthy prison sentence.

‘You haven’t heard? The graphic novel – the publisher pulled out of the contract. Difference in value base; something about a code of conduct.’

She felt sick. Eighty K, most of which she’d spent in her head, no longer. Roddie had worked for years on spec, i.e., unpaid, and thought he’d finally made it.

He’d be counting in fives for the rest of his life.

And she wouldn’t be able to leave work, she’d have to go back to that place till she was sixty-eight and had one polyp per disappointment. So selfish to think about herself.

‘What value base?’ she asked.

‘Either it’s because Roddie’s a wife-beater,’ K said, ‘or it’s because he’s got a wife they wanna beat.’

It was Dawn, the officer on duty when she first interviewed John Paul, who escorted Mary from the governor’s office, through admin, and back down to the agent’s area. Mary was already furious, redmist furious in fact, when they arrived in agent’s, but as she began walking past the glass-windowed interview rooms, her rage became uncontainable, her nose-breathing loud enough for Dawn to say:

‘You okay?’

As they passed interview room eight, she said ‘Aye,’ but it wasn’t true, and it became less so when Mary glanced in room seven.

Derek McLaverty was sitting in room seven. His face caused Mary’s face to explode, the way Renfield did around a century ago. She could feel its severed parts smashing against each other, an eye against a nose, broken tooth against lip, and before she knew it she’d opened the door and barged in.

‘Get the fuck out of my life,’ she said.

‘Excuse me?’ Even in prison garb McLaverty managed to look superior.

‘You do someone a favour to get your polo shirt ironed?’ Mary was disappointed in everything she’d said so far. Her brain was too muddy and her head too hot to be a grown up. The more she looked at Derek, the more he morphed into Tommy McInness, who bullied her at school. Toxic Tommy. Dickwad Derek. All the same.

‘You have a problem with grooming?’ Derek was scanning her matted hair, her broken tooth (she closed her mouth) and the sleeve of her shirt, which was the colour of Sangiovese.

McLaverty’s lawyer, dressed in weekend wear of designer jeans and a black t-shirt, turned to protest: ‘Hey, get her out of here. Dawn! Dawn?’

If Dawn was trying to get Mary out, she didn’t notice.

Derek’s pose was determinedly relaxed: foot on knee, elbow on back of chair.

‘You talked to your mate, didn’t you?’ she said.

‘Which mate?’

‘Rich, RG Books, I saw him chatting on your Cuck Facebook page earlier today. You’ve ruined my husband’s career out of pure badness.’

Dawn put her hand on Mary’s arm; she flicked it away.

‘And you used a vulnerable young boy to try and harm me, right here, in one of these rooms.’

‘Are you feeling all right, Mary? Having a hot flush?’ Derek smiled. Mary lunged forward, but Dawn grabbed her arm and pulled her back.

‘Get out of here,’ the usually flamboyant lawyer said. He packed less punch in jeans.

Being pulled from the room didn’t stop Mary’s rant: ‘You lied about me having an affair, you branded my husband a cuckold. You’ve destroyed him, you fucking arsehole. You get out of my husband’s life, and you get your claws out of my son.’

‘Tell you what, Mary, I’ll get my claws out of yours if you get your claws out of mine.’

Mary broke free of Dawn’s grasp and lunged forward again with the intention of pounding, scratching and biting Derek McLaverty until he died. Dawn had restrained her just in time, but she was still only an inch from him, breathing wet rage into his ridiculously relaxed face.

‘You want to hit me, Mary?’ he goaded.

The answer was yes.

Several sharp nose-breaths later, Dawn managed to remove Mary from the room.

‘He’s an arse,’ Dawn said, putting her in a taxi, ‘but you won’t win that way. You gotta keep the moral high ground.’

Dawn was being kind, but Mary wanted to bite her too.