This one time I was travelling home on the tube. It was after midnight, the time of night that the tubes fill with the not-quite-drunk who have stumbled out of bars and parties onto the last tube home. The time of night that commuters tuck away valuables, avoid each other’s eyes even more than usual, and pull the hems of skirts incrementally down over exposed thighs.

I was travelling with my housemate. She’s French, though she’s lived in London for near a decade. When she talks about her country-of-origin her accent thickens and grows sultry, her eyes unfocus and look beyond you to a half-recollected childhood; she goes places that we can’t follow.

Tonight we were two of only five or six people in our carriage. There was a sour looking man in a great coat who was gazing at his knees, a Chinese woman in the far corner, and a few blond girls sitting together, not speaking. My housemate and I were the only ones in the carriage talking. We were gossiping quietly about the friends we had left behind, blasted and good naturedly tipsy in Notting Hill.

At Southfields the train doors slid open and the carriage suddenly rang with yells, shouts, cat-calls, singing… A tumble of words I couldn’t understand. My housemate jumped and looked over her shoulder, down the carriage to where three men were jostling each other, crowding the doors, calling loudly to each other and down the platform. I caught one phrase: “Au revoir!” they were calling, “Au revoir!”

The blond girls were glaring at them. The man in the great coat was staring fixedly at his knees. The Chinese woman shrank further into the corner. My housemate was smiling a half smile, one ear cocked, listening.

As the train pulled away from the station one man began to sing, slowly and loudly, his voice swelling and filling the carriage. Another joined in, beating time against his thighs and clapping his hands. The girls were looking at each other, smiling, flicking their hair as they shook their heads in irritation. The two men increased the rhythm and looked to their friend who laughed, shook his head and fired off a rapid string of words. “Non, non!” He finished, “Non…” But they kept going, galvanizing him, singing louder and louder…

And then, quite suddenly, he began to dance. A wild, incoherent, whirling dance, his torso bending and spinning down the carriage as his feet tapped heel, toe, toe, heel...

My housemate was laughing and he span towards her, bursting into song with the others as he did so. He passed the girls who gasped; he passed the man in the greatcoat who didn’t acknowledge him at all. He arrived in front of my housemate and looked her straight in the eyes.

“Mon compatriote?” he asked, bowing low and holding out a hand.

They danced all the way to Wimbledon Park and my housemate kept smiling all the way home.