She returned my handshake with a firm grip, her hand dry and warm. I couldn’t believe she hadn’t run off yet. She actually seemed pleased to be talking to me. ‘I’m Charlie when I’m not at work. Are you an Andy?’

‘You can call me Andy if you like.’

She wrinkled her nose. ‘Nah, I prefer Andrew. Sounds more grown up.’

The train clattered into the station and Charlie and I were propelled onto it by the surge of the crowd. We found ourselves pressed together beside the door, other bodies clustered around us.

‘Where are you going?’ I asked.

‘London Bridge.’

‘Me too. Then an overground train to Tulse Hill.’

‘Is that where you live?’

I nodded. ‘How about you? Are you one of those north-of-the-river types?’

‘Oh no. I live in Camberwell. Proper London.’

‘You don’t have the accent,’ I said. ‘I’d guess you’re from somewhere up north.’

She laughed. ‘Yes. That great wilderness beyond the M25.’ She stage whispered. ‘I come from a tribe in a primitive little village called Leeds.’

‘Oh yes, I’ve heard tale of it. You escaped though.’

‘Yes. Though my seventeen brothers are hunting me even as we speak. With specially trained hunter pigeons.’

We talked. Were we flirting? It definitely felt like flirting, though maybe she thought I was an idiot and was awaiting her first opportunity to get away. I couldn’t take my eyes off her face. She was even more stunning than I’d originally thought. She had a little chip out of one of her front teeth, and the heat of the Tube train had made the skin around her collarbone flush pink. I badly wanted to kiss her.

I told her I was from Eastbourne and she told me she’d been to Brighton, which is what people always say, and then we passed Bank and I became aware that we were about to get off the train and would probably get separated. Forever.

‘I just had some excellent news,’ I said. I told her about being discharged.

‘That’s fantastic.’

We pulled into London Bridge. I was going to have to get off. I would never see her again. She appeared to be deep in thought.

‘So how are you going to celebrate being released from Moorfields?’ she asked.

‘I don’t know.’

‘Going to go out with your girlfriend?’

‘I don’t have one.’

The doors slid open and commuters began to push past me. I stayed rooted to the spot, trying to prolong the moment.

I didn’t need to. Before I could gather the courage to ask her out, Charlie took me by the arm and pulled me off the train. We stood on the platform, jostled from all sides. Charlie stood firm, the other passengers flowing around her like water past a rock.

‘Come on,’ she said. ‘I’ll buy you a celebratory drink. You do drink, don’t you?’