After the diagnosis, James wasn’t sure how to ask whether the Edinburgh trip was still on, but Mum insisted. ‘He doesn’t want anything to be different.’ And so up they went, towards the end of August 2014. The train was full of festival performers, cello cases and accordions clogging the luggage racks; pale, earnest young men with hoodies advertising their shows. ‘I wouldn’t have minded being a performer, an actor, you know,’ said Dad, although this had never come up before. Bryson had apparently decided even Australia wasn’t enough for him: this year’s book offered the entire history of the earth.

‘An actor?’

‘Used to do a bit at university,’ said Dad, ‘messing around, revue, that sort of thing. Would have liked to be on the weather-report side of things, on the telly. I did try out for it once.’ James looked across the table at his father. His hair had been thinned out alarmingly by the treatment, and gone grey, bone-white in places. There were liver spots on his hands that hadn’t been there before. He didn’t like the tone of reminiscence; didn’t like the past tense that Dad was starting to apply to himself.

‘Did an all-right job of it, too,’ said Mr Chiltern, sipping his tea. ‘But the chap making the decision was a – what’s the word. Stupid bastard.’ James had never heard his father speak like that before; he snorted some of his own cup of tea and took a moment to recover as Dad went on. ‘Good luck to this lot, going up there and performing. That’s my point. Takes some nerve.’

‘How have you – how are you feeling?’ James managed to ask, after several minutes’ inner consideration.

‘Oh, not bad, not bad at all most of the time,’ said Dad, and James slipped thankfully back into the mental space he’d occupied for the past few months, in which his father’s illness was a regrettable but unchanging state, a problem which could be deferred for ever. A heavily tanned man in a flat cap went down the aisle with a folded-up unicycle over his shoulder. James stood up to help him jam it into the overhead locker, and the conversation spotted its chance and moved on, Dad giving a nearly silent clap to some witticism about cosmic destiny as the train flew up the spine of the country.