‘My husband and I, along with our older daughter, are going out tomorrow to join Beth. A week’s holiday,’ she’d said.

‘Oh, lovely!’ Siobhan responded, but Abi picked up on a certain reticence.

She didn’t question it, and was about to say her goodbye when Siobhan exhaled loudly and said:

‘Look, Abi. I wasn’t going to say anything, but something’s been going on between the girls. Something upsetting.’

‘Oh?’ The basket on Abi’s arm felt heavy all of a sudden, her muscles automatically tensing.

‘It’s this WhatsApp thing they do – Outfit Of The Day.’

‘Right. Beth’s mentioned it.’

‘I’m sure she has,’ Siobhan said quickly, and Abi’s antennae twitched.

‘Lately, whenever Sasha posts a photograph of herself, she is immediately bombarded with questions posted online, asking: Where did she buy the outfit? How much did it cost? What size is it? Did it come in any other colours? These are just some of the questions – there are normally many more. It’s the same with every single outfit she posts – instantly the questions start, ten, twenty messages in a row. I know it sounds silly, but it really bothers Sasha.’

‘I imagine it would be a little annoying,’ Abi replied carefully.

‘Oh, more than annoying,’ Siobhan countered swiftly. ‘It’s intimidating. Some of the questions are just downright mean, suggesting that Sash looks fat or unhealthy.’

Her smile was gone now. A strident tone had entered her voice as she clutched the handle of her trolley, a challenge there in her eyes.

‘Hang on a second,’ Abi said, trying to adopt a reasonable tone. ‘Are you saying that Beth has been intimidating your daughter?’

‘Yes.’

‘You’re sure about that?’

‘She’s been posting the messages under a false name but everybody knows that it’s her.’

‘Oh, come on—’

‘And when Sash confronted her about it, she didn’t deny it. It’s online bullying.’ Siobhan’s face had gone quite red.

‘I really think you’ve misunderstood. Even if it is Beth, it sounds to me like she was just trying to join in, granted in a clumsy way. But instead of being nice about it, Sasha has shunned her.’

‘Now, just a minute—’

‘In the same way Sasha and her little gang shun Beth at school. Constantly.’ Abi’s voice had risen, and she saw the flash of indignation in the other woman’s eye.

‘I don’t want to have an argument about it,’ Siobhan said, mustering up some dignity. ‘But if it continues, I’m going to bring it up with the school.’ She fixed her handbag on her shoulder and pushed her trolley forward towards the end of the aisle, but before she rounded the corner, she looked back at Abi and said, her voice wobbling a little: