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.