All told, I find that in the last week I’ve slept with a Chinaman, three black women from the United States, four South Korean women and one South Korean man.

I slept with the South Korean man first, for two nights running, at the Chameleon Hostel in Alicante. Joon-woo and I shared a 9’ by 8’ four-bunk cell. We were both on the bottom, 18 inches apart. This quiet, cheerful chap was always showered and in his black pyjamas and yellow duck head slippers by 9 p.m. and fast asleep by 10. He slept silently and soundly and with no discernible movement until 9 or 10 in the morning, when he would greet me with the same smiling equanimity with which he had said goodnight. He had been in Spain for 40 days, he said, visiting the stadiums of lower league Spanish football clubs. So far he’d clocked up 22. He had heard that Britain had the worst food in Europe, an accusation which boggled his mind, he told me, because he couldn’t imagine anything worse than Spanish food. Although he was too polite to say so, I formed the impression that he found Europe a decaying, inefficient, third world sort of a place, and that this was a great surprise to him.

The four South Korean women and I slept together in a six-bunk dormitory at the Go! Hostel in Alicante. They were all slender and darkly pretty and seemed to find everything uproariously funny — including their first sight of the 60-year-old depressed Englishman they found tucked up in his bunk at 9 o’clock in the evening reading Heart of Darkness by the light of a head torch with a broken strap. They literally fell helplessly about, clutching their sides and crying. They went out laughing together and came back laughing at 2 in the morning and started laughing again the moment they woke the next day and saw me standing up in my Marks & Spencer underpants rifling through my luggage for my morning medication. In the hostel common rooms they were amused and amusing mixers, but other nationalities seemed to disappoint them. I’d never met a South Korean before last week, let alone shared a bunk with one, and I decided that of all the young travellers of various nationalities I had met in Spain so far, I liked the South Koreans best.

The Chinese guy I slept with in a two-bunk hostel room in Almeria. He was wafer-thin, almost evanescent. When he told me he was from China, I asked him what he thought about Donald Trump’s political strategist predicting certain war between the US and China in ‘five to ten years’. He was sitting on his bed looking at his phone at the time, and the idea disturbed him so profoundly he refused to either look at me or talk to me after that and he carefully avoided me in the dining room.

The three black American girls arrived as I was getting ready for bed in a six-bunk dormitory at the hostel in Seville. They had come on the last bus from Lisbon. As the hostel manager showed them in, I was on one unstable foot and drying the toes of the other with my towel after a shower. An awkward moment, but they were indifferent to the abysmal sight, merely stating as they edged past me that if they didn’t eat soon they would all die. The dormitory was blessed with an en suite tiled shower and lavatory with incredible acoustics and powers of amplification, which they used one by one, and just in the nick of time by the sound of it.

While they claimed their respective bunks then got ready to go out again to get something to eat, I climbed into my berth, adjusted my head torch and returned to the bend in the upper Congo river. But more captivating even than Conrad’s prose was the vision of these Three Degrees standing in a row not two feet away holding up vanity mirrors and brushing powder on to their cheeks and applying mascara and lip gloss. As they brushed and painted they asked me about Seville over the tops of their mirrors. What did I recommend they see first?

‘Without a doubt the Plaza de Toros de la Real Maestranza de la Cabelleria de Sevilla. The bullring,’ I said. ‘The bullring. Okay,’ said one, making an O with her mouth. ‘I could eat a bull right now,’ said another, hopefully. ‘Break off the horns and wipe its ass and just bring it,’ snapped the third. They served bull’s balls in baps in the café next door, I said, helpfully. ‘We’ll take a cab,’ they said, and off they went. I mentally moved young black urban Americans right up there with the South Koreans, drew the bunk’s little curtain, settled back on the pillow, and intruded myself back inside the tiny cabin where Kurtz lay emaciated and dying on a stretcher.