‘Because …’ Fran repeats, distracted by her reflection in the mirrored doors. She looks small, and round, and old. How did that happen? ‘Because what happened wasn’t your fault. As I said, the man’s a deviant and I would be more than happy to get off at your stop and report what happened to a member of the TfL staff. Or the police.’

As she looks back at Stella she is surprised to discover she’s grinning.

‘What?’ Fran asks. ‘What did I say?’

‘Nothing. I just … it’s refreshing. You’re refreshing.’

Fran’s not entirely sure she wants to know what that means so she doesn’t question her further. Instead, she asks Stella where she’s getting off and offers to accompany her to the nearest police station.

‘West Hampstead.’ Stella glances at the huge bag of books that Fran has left on her seat. ‘And that’s really kind of you but I think you can report this sort of thing online. Can I take your number anyway, just in case the police need to speak to you?’

‘Of course.’ Fran rummages in her bag for a piece of paper and a pen and scribbles down her mobile number and full name. ‘Do you have family? At home. Can you get there safely?’ Her throat tightens as she imagines Stella stepping out of the tube station and vanishing, never to be seen again. It happens; she knows that well enough.

‘I’ll be fine,’ Stella says. ‘I’ve got flatmates. I’m angry more than anything. If the tube hadn’t been so packed, I’d—’ She breaks off as the train crawls out of the tunnel and pulls to a stop at West Hampstead station. ‘Shit, this is me. Thanks for this.’ She plucks the piece of paper from Fran’s fingers. ‘And for doing what you did.’

Fran shrugs. ‘Not a problem.’

As the train doors open Stella moves to get off then turns back. ‘Hug?’

Fran stares at her in horror. What’s the polite way of saying no? Is there one when the girl’s just been sexually assaulted and is in need of physical reassurance? Should she just say yes and grin and bear it? A dozen different responses run through her head but the one that comes out of her mouth is, ‘I’d rather we didn’t.’

Stella laughs. ‘Bye Fran, thanks again.’

As Stella bounds off the train, Fran’s mobile vibrates in her handbag. She fishes it out and taps in the password. Her mum has sent her a WhatsApp message. Fran clicks on it and squints at the black and white image. It looks like a newspaper article. She digs around for her reading glasses and puts them on.

She recognises the face in the photograph – the dark hair, the strong jawline, the piercing grey eyes.