Arthur was sitting in the corner, sipping a pint of beer. His head was bent over a newspaper and he looked like all the other travellers, whiling away a few hours on their journey home.

I wasn’t sure what to do but Arthur made an easy move in our direction. He seemed surprised by our sudden appearance. I wasn’t convinced.

‘Rebecca. What a small world!’ He folded his newspaper and tucked it neatly under his arm like a seasoned commuter; but he wasn’t a seasoned commuter. He worked out of local premises a mile from his flat in Highgate. That was the story I remembered.

‘Arthur, how weird.’

‘Aren’t you going to introduce me?’ My mother fiddled with her hair in a bizarrely flirtatious manner and extended an arthritic hand in the stranger’s direction.

‘You must be Rebecca’s sister,’ Arthur joked. ‘Here, let me buy you ladies a drink. I’ve a couple of hours to kill. What would you like?’ He didn’t flinch nor comment on the unlikelihood of the event.

‘A sherry, a large one please.’ My mother had perked up. A pink tinge brightened the deathly pallor. She ignored my meaningful stare which hinted at caution and uncertainty.

My mother wasn’t going to pass up male company. Women bored her. Her twenty-year-old self rose spectacularly to the surface in a display of self-delusion. I watched on helplessly. Arthur ordered me a large glass of red wine, it was Christmas after all, and another beer for himself.

We settled tightly round the table, pinged our glasses together, and became locked in our own seasonal pantomime. I waited until my mother made a trip to the Ladies’ before I spoke.

‘What a coincidence. Do you come here often?’ Light flirtation was aimed to put him at his ease and ferret out the truth.

‘I’m on my way home to see my family. Well, my mother. She comes from Cambridge.’ He smiled with familiar ease and for a moment I was ashamed of doubting that our meeting was more than coincidence. Arthur’s plausibility was faultless.

‘I leave it to the last possible moment before going home. Always have done. She’s not an easy woman,’ he said. Perhaps he’d read my own relationship with my mother, quickly and cleverly, and aimed at collusion.

Mum returned from the Ladies’, bright blusher applied to her sunken cheeks. Pink lipstick outlined her thin lips, faint streaks seeping through the wrinkled tributaries. She was walking more upright, making a deliberate effort to straighten her ageing stoop.

‘Arthur, are you married?’ The large sherry was followed by another and I sat back and watched the developing camaraderie.

‘Imagine, Arthur lives up the road from you.’ This time my mother didn’t miss my angry stare. I glowered at her, willing her to be quiet. I didn’t want Arthur to know my address.