The sun hovered on the horizon. Within twenty minutes it would set. The patients who were well enough tied and retied their headscarves or washed their hands in the sterile washbasin outside the recovery ward in preparation for Maghrib, the sunset prayers.

They were six men from the same village near Gao, Ali among them. They spread out their prayer mats. She watched their genuflections, the way their heads touched the mats so lightly before springing away, as if the ground had delivered them an electric shock.

After prayers he found her in her office. She saw his feet first, beyond the flap of her door. They were slim and sinewy, they reminded her of leather bridles.

She asked him to sit. He folded his body with great fluidity, considering his injury, sustained a week before.

‘Why do you watch us at prayers?’

‘I don’t know.’

He nodded, satisfied, she could only suppose, with the honesty of her response.

‘Why do people walk dogs in the rain?’

‘What do you mean?’

‘On television, once, I saw people in England, in a green space. A park.’ He landed upon the word as if he had only just learned it. ‘They had their dogs on strings.’

‘Leads. Dogs have to be walked. It doesn’t matter what the weather is.’

‘Ah.’ His eyes flared. It occurred to her he might be hungry for conversation, nothing more. At times in Gariseb she felt this same famine blow through her, a hunger for abstract thought as much as anything. Her mind now was stuffed with facts and actions.

‘How is life in Gikayo?’ she asked.

‘It is bad.’ His expression was solemn.

‘Is it a big place?’

‘Normally there are two thousand people. It is a large village.’

‘Normally?’

‘Now there are three hundred refugees also. But they live apart. They have their own quartier.’

‘What are they refugees from?’

‘Al-Nur.’

‘Why do they fear them?’

‘Because Al-Nur will change their laws. Until now they have lived like Kufir.’

‘I don’t think so. They have been observant Muslims, but they have had freedoms.’

He considered this with a reasonable expression.

‘Are they right to be afraid?’

‘In Gao, yes. Al-Nur now control most of the city. Eighty per cent. But you know that.’

She played with the pencil on her desk. ‘How would I know that? We are three hundred kilometres away here.’

He did not answer. Ali was the exact person the refugees of Gikayo were trying to avoid, she knew – a fighter, or a spy from the security wing, who policed social behaviour. Women found outside without their husbands were shot in those areas now controlled by Al-Nur. Or at least that is what her security briefings in the Chequers mansion had taught her. The security wing of Al-Nur were impossible to spot because they were ordinary people: shopkeepers, tailors. Spies were everywhere.

He was still looking at her.

‘And your camels, are they well?’ she asked.

‘Very well. My father has fifty.’

‘Then your family is secure.’

‘Yes,’ he said. Something of him relished the word, she thought. Secure. Safe. His hunger for language was one of the characteristics she could relate to, as well as his precise yet unfussy speech, which gave him an instant gravitas. You almost feel you could trust this man. More and more her thoughts had taken on this quality: mental compositions she would later send to Anthony, requisitioned from afar. No longer her own.

‘What do you think of Al-Nur?’ she hazarded.

‘What is wrong with my country is that it is not a country. It never has been. For two hundred years the British have been trying to turn it into something they can recognise, and so control.’

She didn’t argue with this explanation, even if he had evaded her question. It was broadly true.

‘Have you ever thought about leaving your country, living somewhere else?’ she asked.

‘My country does not yet exist,’ he said.

‘It does. But it is eating itself alive.’

Ali did not shrug – the fighters she treated did not seem to have that gesture in their physical vocabulary. Instead they flared their nostrils and flashed their eyes in indifferent disdain. ‘I can’t leave. We need to become a country. Then perhaps I will be a diplomat.’ He beamed at her, a sudden, innocent smile. ‘Before, it was possible to be a tribal kingdom or a religious state. But now the world requires countries in order to engage with you. We must be realistic. But the country needs to be under Islamic law, like Saudi Arabia.’

‘Why?’

He laughed out loud. Her question was that preposterous, she supposed.

‘Because Sharia law is a good law,’ he said. ‘The people respect it. The mosques are always completely full. There is no going back now. The people prefer it to socialism. They remember only hunger of those years.’ He paused. ‘A country needs resources. Angola has diamonds, Botswana copper. Even Sudan has oil. We have camels, and sand.’

‘You want to enrich your country?’

His eyes narrowed. Most people did this involuntarily. It was part of the parasympathetic nervous system, like blinking, or breathing, but his reaction had a deliberateness about it. She wondered where, or how, he had learned to become such a self-contained, an entity, an uncrackable egg.

There were four reasons why men like Ali became guerrilla fighters, she had learned long ago, courtesy of the army and its seminars pre-deployment and post-deployment, conversations with logistics experts, and then those long, dry weeks and months in the field. They had sent an instructor, a Sandhurst-educated strategist in sandy fatigues.

The first reason was called political but was often territorial: to dislodge an interloper, an unfair regime, a sadistic warlord. Then, to change the world, to upend a corrupt system and suspend the false consciousness that made its existence possible. ‘Ideology. The Che Guevara motive,’ the instructor had said.

The third was identical to the political motive but with a twist: religious indoctrination. Religion was a façade for ideology, which was a façade for power. Finally, the fourth: bad luck – you were caught up in events, you came to consciousness in a civil war, your parents were killed, you drank revenge like boiling petrol and it fuelled you, you had no choice. The four reasons could coexist, the army major said, but one rationale always trumped the others.

She tried to see behind the veil of Ali’s eyes. She failed to find the rancid hatred of the religious ideologue, or the ordinary fury of the politically motivated. If history had not come along and bullied Ali into war, he might have been exactly what he looked like – a village schoolmaster. Perhaps, with luck and the right connections, he might even have risen to be minister of education for a region or a province.

She thought of all this as he began to tell her a story. At its start she took it for a follow-up to his shark parable. The story was about his uncle – or perhaps his cousin, she missed the exact tie – ‘A very important man,’ Ali said. His name was Mohammed Ibrahim and he was a religious elder in Gikayo.

‘He was about to take over the area. He was the second in command to Omaar.’ He said the name as if he expected her to know it. ‘He would have changed everything. He was educated in London, he was a real statesman.’

‘What happened?’

‘The daughter of his cousin came to visit. He was very fond of her. He was a careful man, Ibrahim. He had everyone who came into his compound frisked, even his servants of thirty years. But Zainab didn’t like being frisked by men. She told Ibrahim it was un-Islamic.’

‘Zainab killed him?’

‘And herself.’ Ali nodded once, then twice, as if to seal a deed.

The diesel generators sputtered into life. It was dark now.

Ali folded himself back into an upright position with a deliberate, angular grace. She left the tent with him and watched him glide into the night. Overhead the stars were punched into an implacable, black sky. One moved suddenly, spewing a shower of light in its wake.

‘It’s the international space station.’ Suddenly, Andy was beside her. Where had he come from?

‘Really?’

‘I’d show you it on the NASA site if we had the bandwidth. They’ve passed over here before.’

‘There they are, twisting knobs or whatever it is they do up there in zero gravity, with us down here.’

‘Yeah,’ Andy said. ‘It must feel great to be above it all.’

He was quiet for a moment. ‘I see you’re getting along with Osama bin Laden.’

‘What makes you say that?’

‘He’s well-educated.’

‘He is,’ she conceded. ‘But not that well-resourced. Although he was in charge, definitely. Is in charge.’

‘How do you know?’

‘Aisha recognised him.’ She looked at him quickly. ‘It’s important he doesn’t know.’

‘Sure thing.’

Aisha had waited three days after he had first arrived to tell her. She came to find her on the edge of the camp, where she had gone to check on her camel.

These men, they are different. Foreigners.

From where?

Arab countries. Not Africa. They use false names. Aisha’s mouth sank in disdain. They speak Arabic – pure Arabic. They have come with guns for our men. There is one man – I don’t know his name. He is the leader. He looks like a schoolteacher, but he is very brave. No. She switched words. Brutal.

Aisha had not actually seen him, she’d told her; she’d heard his voice on two of the nights she’d spent in the desert in hiding. It was Ali and his men she was hiding from, although neither of them knew it. As they passed nearby, Ali was speaking to his men. ‘Something about Gikayo,’ Aisha said. Aisha had passed through the town, although at the time she did not know its name, on her long pilgrimage from her home. Gikayo was where she had lost her last remaining camel, bar Montague. She had been too afraid to move from her hiding place, and had to listen as he was trapped by a group of men and butchered alive.

Andy peeled away from her and walked towards the accommodation block. She never knew what to make of his visitations. She had the impression he was watching her, and not with ordinary curiosity. Or there was a more specific reason: to catch her out in the act of making an avoidable mistake, maybe. Or some other motivation – something she had not even thought of.

She would talk more to Aisha tomorrow. Then she would make up her mind.

As she walked across the compound she saw Mustafa. She nearly used the greeting she’d learned in war zones. But you are alive!, the childlike glee that powered it. There was no point in saying hello, or how are you? You were there. You were not a ghost. Not yet.

‘How long is it since I have seen you?’ she asked in Arabic.

‘Long enough, Inshallah.’

The twenty-one-year-old had a rangy but gentle smile. He was one of the cross-fire casualties from the village. He had nothing to do with Al-Nur, she was sure of it. In two days he would be well enough to go home to his goats. At this news he gave her an instant smile. All of the Bora men she had met performed these quick-change expressions, lurching from a sombreness to childish, reckless smiles.

She said goodnight to Mustafa. She didn’t know what she would do that evening. She would have a tea, stare at the ceiling, or just sleep. She dreaded the questions that came with these bleached hours in camp. What has she become? Has she lived a life worth living? Why did she fail to grasp the present, even when it slid over her?

She missed the city – any city. She’d been in the capital only three days before flying to Gariseb, and that was four months ago now. She wanted desperately to be in a city again. There, she could have a drink, she could watch strangers – people who she would not have to eat three meals a day beside for months on end, whose names she would never know. It was not sex she wanted. In any case sexual desire was always abstract, for her, until attached to another person. It was a moral decision, in part. But also she had never felt the kind of physical hunger that drove others to sleep with strangers. She took intimacy seriously. But she liked to observe people who did not, who circled each other languorously in the city’s bars and clubs like cheetahs. She felt superior and left out at the same time. She kept her loneliness intact.

He came to find her the following afternoon. He repeated his entreaty. ‘I would like to listen to the radio.’

‘I will need to discuss with the others,’ she said. This was the tactic she used, with impossible requests, learned from observing village elders and their dispute-settling tactics. The invitation to sit under a tree cross-legged and eat dates was like a magical potion.

He turned his liquid eyes towards her. ‘I had a dream last night,’ he said. ‘I was riding a black horse. There was a full moon, but around it was a green colour, like a shadow. It curled around the moon. I could not decide if this was a good omen or bad. I had a horse because there were no trucks. Perhaps it was a time before trucks. The horse was black, and we had come from the city together. What city, I don’t know. There were black birds in the sky and I didn’t like this either. Black birds flying towards the mountain. Where I come from, this is always a bad sign.’

‘Why is everything either a good or bad sign?’

‘Birds are intelligent.’

‘They are,’ she agreed. ‘But they don’t know the future.’

He looked at her with an expression that might have been shock.

She was tired. The future: she felt its bully burden through these people she treated, she felt the eyes of God and his intentions. From now on she would have to stop herself from looking at a flock of migrating black starlings and seeing the dark coagulations of fate.

She ran a hand through her hair. Dust and oil coated her fingers. Water in camp was low; she hadn’t showered in days.

Ali had turned to leave.

‘Perhaps we can listen to the radio together,’ she said. ‘It’s on my computer. I can stream a radio station once in a while. I’ll have to work, I must write up my notes. But I can listen to it in the background.’

She had a vision of Anthony and his team calling up the World Service for the files, listening to the broadcast over and over again in the company of two simultaneous translators from the Bora refugee community commandeered from Tottenham that morning, in a room with a smooth conference table made of pale wood and the grey snake of the Thames in the distance, trying to parse what message might be encoded in these broadcasts Ali was so keen to hear.

‘Tomorrow, come at noon.’

A smile spread across his face, slowly at first, then rapidly gathering force. He was a wire; he transmitted information. Even his hands and fingers were fine, like antennae.

The sun was setting. She had not had a drop to drink for three months. She had not tasted yoghurt or fresh fruit, apart from hard, pitted oranges. Their bitterness was a tonic; it had within its bite an honesty, as if only in denial would she discover the true taste of sweetness.