La Paz is what Dyer understood Rougetel to have meant, but when Dyer thought about it later he was not so certain. Rougetel wasn’t a joker. Maybe his mind had slipped. Maybe he was an unstable fantasist. Or maybe he had been telling the truth, he did come from outer space, and all other people on earth were the aliens.

At any rate, he still had a look of great sincerity, he hadn’t lost that. His need to know what was true, what was not, had been a permanent crease in his character, like the dent in his chin. Rougetel’s hankering to get to the nub was the quality that had attracted Dyer and soldered their friendship. They had forged something between them at the Phoenix, an understanding, the kind that trained its compass points on worlds yet to be encountered.

Their meals arrived, and Dyer lost what he was going to say.

Across the table, Rougetel ate with his fingers, in haste. He was not ashamed of his hunger. His teeth were yellow, uneven.

Dyer felt self-conscious, picking up a knife and fork. He had become aware of a queer smell – not urine or body odour, but musty, vegetably, and overlaid with a powerful lemony scent. It was the smell, he realised abruptly, of someone who slept in the open.

He lifted his head very slightly to observe Rougetel swallowing down his food. He wasn’t dressed like other homeless men in Oxford, as though in the uniform of a defeated army. His clothes were clean; not ironed, but clean. Even so, he looked grindingly poor.

The canvas oilcloth stretched tight over the table.

Dyer said: ‘I last saw you—’

‘On the river bank near Hampton Court,’ said Rougetel. His tongue was creamy with falafel. ‘You’d been rowing.’

‘I used to row with the Molesey Boat Club in the long vac.’

In the slightly guarded and watchful way that was part of his character now, Rougetel peered into Dyer’s face.

‘What did you do after university?’

Dyer wanted to tell him: how he had abandoned a doctorate, become a cub reporter, then a special foreign correspondent in Latin America, back in the day when Rio was still. His decision to take the job in Brazil, at the time warmly supported by Vivien, was the fruit of a wild seed that Rougetel himself might have planted, with his vivid schoolboy descriptions, spiced with Spanish and Aymara, of the Andes, the native communities on the Altiplano, and the orange-roofed villa in the Achumani district of La Paz where the Rougetels lived.

‘I did try and look you up,’ Dyer needed him to know. In his second year in Brazil, his newspaper had sent Dyer to the Bolivian capital for an article on the Dia de los Muertos. Yet no Rougetel was listed in the telephone directory. ‘No one at the Embassy had an address for you.’