But there’s a problem. Looking back down the street I see that a silver-grey Citroën C5 has double parked beside my Audi, completely boxing it in. The hazard lights on the Citroën are flashing but there is no sign of the driver. If Sellini leaves now, I will not be able to follow him. Alfonso is coming down the ramp behind me and he hails the first of the two cabs, which leaves its station and drives quickly up the slope towards the entrance of the hotel. Then, just as I have made the decision to abandon my car and follow by cab, a man wearing a pin-striped suit steps into the back of the second taxi and drives off.

Why did I think I recognized him?

This is now serious. Turning to face the oncoming traffic I begin a desperate search for another taxi. Two come past, both occupied. If the driver of the Citroën doesn’t appear in the next thirty seconds I will lose Sellini. He may not even be going to Barajas; he may have told that to Alfonso simply to set a false trail. His cab is coming down the slope from the entrance of the hotel and preparing to make a right-hand turn north along the Castellana. Sunlight reflects off the back windows but I can still make out his slumped silhouette. As he pulls out, I open the driver’s door of the Audi and press on the horn, more in anger than in expectation, but still the driver of the Citroën does not appear. Another full cab whips past as Sellini’s disappears into the distance. The sound of my horn is deafening, long blasts followed by short, incensed bursts that begin to draw stares from passers-by.

At last a pedestrian comes ambling up the pavement dangling a set of car keys in his left hand. Relaxed and oblivious. This must be him. I release the horn and stare as he makes guilty eye contact and quickens his step. He’s about my age, with brown hair and puffy, freckled skin, wearing jeans and a white cotton shirt. At first glance I would say that he is a British tourist but I speak to him initially in Spanish.

‘Ese es tu coche?’

He doesn’t respond.

‘Hey. I said is this your car?’

Now he looks up and it’s clear from his expression that he failed to understand what I was saying. To avoid a confrontation he may walk past and pretend that the Citroën does not belong to him. I won’t let him get away with that.

‘Do you speak English?’

‘Yes I do.’ The accent takes me by surprise. British public school with the privilege stripped out of it. BBC. Foreign Office.

‘I think this is your car. I think you blocked me in.’ We are facing one another on the pavement just a few feet apart, and something about the man’s level gaze and apparent lack of concern for my predicament serves only to deepen my sense of anger.

‘What seems to be the problem?’ he says. The question is just this side of sarcastic.

‘The problem is that you blocked me in. The problem is that you prevented me from doing my job.’

‘Your job?’

He says the word with a slight edge of ridicule, as if he knows that it’s a lie.

‘That’s right. My job. So do you want to move? Can you get your car the fuck out of my way? What you did was illegal and stupid and I need to get going.’

‘Why don’t you calm down, Alec?’

He might as well have dropped a low punch into my stomach. I feel winded. I look into the man’s face for some distant trigger of recognition – Was he a student at LSE? Did we go to school together? – but I have never seen this person before in my life.

‘How do you know that? How do you know who I am?’

‘I know a lot of things about you. I know about JUSTIFY, I know about Abnex. I know about Fortner, I know about Katharine. What I don’t know is what the hell Alec Milius is doing in Madrid. So why don’t we hop in the back of my car, go for a little drive, and you can tell me all about it.’

25. Our Man in Madrid

‘Before I get into anybody’s car, I want to know who the hell I’m talking to.’

‘Let’s just say that you’re talking to a Friend,’ he says, employing a standard SIS euphemism. A woman walks past us and looks at me with a twist of worry in her face. ‘Better if you keep your voice down, no? Now let’s get in the car and head off.’

Once inside he frisks me – shins, calves, back of the waist – and seems to take a perverse pleasure in asking me to fasten my seatbelt. I try to summon a suitably hostile look to meet this request, but the heat of sweat and panic I can feel in my face has stripped me of any authority. I drag the seatbelt down and clunk it into place.

‘My name is Richard Kitson.’ On closer inspection he looks closer to forty than thirty, with a face that I would struggle to describe: neither ugly nor good-looking, neither smart nor stupid. A vanishing Englishman. ‘Why don’t we head up to the M30 and drive around in circles while you tell me what’s on your mind?’

For the first couple of minutes I say nothing. Occasionally Kitson’s eyes will slide towards mine, a sudden glance in traffic, a more steady gaze at lights. I try to stare back, to meet these looks man to man, but the shock of what has happened appears to have robbed me of even the most basic defensive reflexes. After six years on the run, it has finally come to this. I am shaking. But why was Sellini involved? What did he have to do with it?

‘What’s your interest in Abel Sellini?’ Kitson asks, as if reading my mind. ‘You buying drugs, Alec? Acquiring some weapons?’

‘Excuse me?’

‘You don’t know who he is?’

‘I know that he probably killed a friend of mine.’

‘Well, you see, that’s exactly the sort of thing you and I need to talk about.’

‘You first. What are you doing here? How do you know who I am? How do you know about JUSTIFY?’

‘One thing at a time, one thing at a time.’ A black BMW overtakes us on the blind side, gliding past my window. Kitson mutters, ‘Bloody Spanish drivers.’

‘OΚ. One: how do you know my name?’

‘Took a photo. Pinged it back to London. You were recognized by a colleague.’

Jesus. So I was right about the surveillance. In a simultaneous instant of horrifying clarity I recall exactly where I saw the man in the pin-striped suit who got into the cab. At the Prado. With Sofía. Lead on, Macduff.

‘How long have you been following me?’

‘Since Friday last week.’

The night I tailed Rosalía to the Irish Rover.

‘And this colleague who recognized me, what was his name?’

If Kitson doesn’t come up with something I recognize, I can assume he’s an impostor.

‘Christopher Sinclair. Chris to his friends. Happened to be passing a desk in Legoland when your JPEG popped up. Nearly dropped his cappuccino. Sends his regards, by the way. Sounded very fond of you.’

Sinclair was Lithiby’s stooge. The one who drove me to the final meeting at the safe house in London on the night they killed Kate. Said that he admired me. Said that he thought I was going to be all right.

‘So you’ve read my file? That’s how you know about JUSTIFY?’

‘Of course. Ran your name through the CCI and got War and Peace. Well, Crime and Punishment, anyway.’ Kitson seems to have a supercilious sense of humour, as if he would be incapable of taking anyone, or anything, too seriously. ‘Quite a story, hadn’t heard it before. You had them in knots for a while, Alec, and then you did the runner. Nobody knew where the hell you’d gone. There were rumours of Paris, rumours of Petersburg and Milan. Nobody pinned you to Madrid until last Tuesday.’

I do not know whether to be offended that Kitson had never heard of me or delighted that six years of anti-surveillance has paid off. I am generally too shaken and confused. ‘And that’s why you’re here? To bring me in?’

Kitson frowns and glances in the rear-view mirror.

‘What?’

‘I said, is that why you’re here? To bring me in?’