My latest bed partner is a seven-year-old lad. That first night we slept together in my double bed, I hardly got a wink. Vivid dreams made him lash out at me in his sleep with kicks and flailing arms. In the morning I opened my eyes and his clear blue eyes, three inches from mine, were studying me.

‘Did you have nightmares, Oscar?’ I said. The eyes considered. ‘Not nightmares,’ he said judiciously. ‘Dreams.’ ‘What about? You were kicking and punching me all night,’ I said. ‘I dreamt Dominic came to my school, and we didn’t do any work, we just played football all day.’ Dominic was Oscar’s best friend at his old school. Dominic is a gigantic boy and a Newcastle United supporter. Oscar is little and has plumped for Manchester United — a tragic choice. He has recently begun at a new school and his new best friend is called Kye, who I think is a boy. Apart from missing Dominic, Oscar likes his new school. It is a progressive school. His last reading and comprehension homework passage, which he and I completed together, was a multiculturalist anti-hunting tract. My duty as his grandfather, I felt, was to point this out to him.

Oscar now lives with his mummy instead of his daddy because his daddy got married and moved 50 miles away to be near his new prison, at which he is a prison officer. He passed out in March from his three-month training course in the Midlands, and on my desk I have a photograph of him, taken a few minutes later, standing proudly in his uniform. For the past three years he has stayed at home looking after Oscar and his younger brother while his fiancée went out to work. Keeping regular working hours again has been a shock to his system. And being a green young officer at a Category C prison has not been without its stresses, I imagine. But the prison governor has stuck Oscar’s daddy on the induction wing and he’s slowly getting the hang of it, though he has hardly a minute to himself from the start to finish of each shift. The bodybuilding prisoners are massive, he says, and there’s plenty of overtime if he wants it. Smoking is to be banned at his prison in the summer. Good luck with that, son, I said.

At his mum’s place, Oscar has two older sisters and an older brother to play with and fight against. And there’s his Mum’s boyfriend, who is a bodybuilder and eats lots of eggs. They live in a town centre above a hairdressers and there is a sweet shop right next door. After Oscar told me about his football dream, he reached down for his iPad and showed me the videos he made the other day. One showed his mummy dead to the world in bed; the other was of his sister lying in bed playing a video game. Oscar positioned the tablet sideways in front of my face so I could watch without moving my head from the pillow. I only had to keep my eyes open. The video of his sister was a ten-minute-long art house-style movie, in which we saw only his sister’s fingers on the device as she massacred zombies and heard her singing softly and melodically to herself above the electronic sounds of the slaughter.

I had landed back in England the previous evening, at teatime, at Bristol airport. I passed in perpetual motion from seat 9C of the plane to the bus stop outside Bristol airport in 16 minutes flat, and stepped straight on to the shuttle bus to Bristol Temple Meads railway station. There I bought a rail ticket and a traditional Cornish pasty and 20 minutes later I was speeding across the Somerset Levels past cattle up to their knees in lush pasture stage-lit by golden evening sunlight, past village churches and manor-house farms with geese, past brimming streams and sluggish rivers, and past the Iron Age hill fort of Cadbury Hill. I had been away from England for a long time and looked out of the window with a stranger’s eyes.

At Newton Abbot station, by arrangement, Oscar was waiting on the platform wearing a backpack almost as big as he is. I stepped down from the carriage. He and his mummy’s boyfriend were the only people on the platform. Oscar saw me and sprinted with his arms outstretched and a cry of ‘Grandad!’ and leapt into my arms, a moment I’ve looked forward to for weeks. We’ve slept together for three nights so far, he and I, and every night he’s dreamed of playing football and every night I’ve taken a bit of a kicking. He loves his football, does Oscar.