IT'S LATE, you're travelling west on the Piccadilly line, towards Heathrow. The carriage is quiet. An old man half asleep. A young couple who aren't talking. He's playing with his phone, she's staring out the window at the darkness of the tunnel. And you.

Hammersmith, that's where she brought you to the Apollo for your birthday to see Paul McCartney.

He was playing a pre-tour gig, trying out new songs, playing some old favourites. We Can Work It Out. You were close enough to the front to watch his fingers move from Bm to G to F#7 when he sang that life is very short and there's no time for fussing and fighting, my friend. You waited all night for Blackbird, but he never played it.

South Ealing, the doors open and no one gets on, but they shudder when they close again, make a loud noise, reopen, then close quietly. The boy looks up from his phone. You know he can't be texting, there's no signal here. He must be playing games.

Northfields, and you remember the moment she told you about the baby. You didn't know what to say at first . . . you thought you'd been careful, after all . . . but she'd seemed excited and you liked her anyway so you smiled and said it was the best thing that had ever happened to you.

Osterley, where you visited some friends for dinner and she felt the first kick and made you put your hand on her stomach to feel it, even though you didn't want to. Everyone looked at you, expecting you to say something poetic when all you wanted to do was answer with a group of synonyms for depressed. And terrified. And pissed off. And trapped.

Hounslow West, and you look down at the backpack in front of you. Your phone's in there somewhere but there's no way you can switch it on.

She'll have got your note by now. She'll have woken up to feed the baby and found it. She'll know what you're doing. She'll be calling to bring you back. But you can't go back.

Terminal 1, and you take the phone from the bag and place it on the seat beside you. The girl sees you do it but she doesn't say anything as you all stand up and walk towards the open doors. She looks at it, looks at you, and your eyes meet.

Without any words, you tell her to mind her business.

The escalator is broken and you have to drag your bags up the stairs towards departures.

You don't know if you can do it. Just get on a plane and go somewhere. Anywhere. A place you won't be found. It's late now and there aren't that many destinations still flying at this point. But every one of them seems a better option than staying here.

The ticket desk. A one-way ticket. Anywhere, you say to the girl behind the counter. I don't care.

Anywhere at all. Tonight.