I turn to Murdah. ‘Tell them,’ I say.

He shakes his head. Not a refusal. Just confusion, and fear, and some other things. I takeafew steps towards him, which makes Benjamin jab the air with his Steyr.

I have to keep going.

‘Tell them what I’ve said is true,’ I say. ‘Tell them who you are.’

Murdahcloses his eyes for a moment, then opens them wide. Perhaps he was hoping to find kempt lawns and white jacketed waiters, or the ceiling of one of his bedrooms; when all he sees is a handful of dirty, hungry, scared people with guns, he slumps down against the parapet.

‘You know I’m right,’ I say. ‘The helicopter that comes here, you know what it’s for. What it’s going to do. You have to tell them.’ I take a few more steps. ‘Tell them what has happened, and why they’re going to die. Use your vote.’

But Murdah is spent. His chin is down on his chest, and his eyes have closed again.

‘ Murdah…’ I say, and then stop, because someone has made a short, hissing sound. It’s Bernhard, and he is standing still, looking down at the roof, his head cocked to one side. ‘I hear it,’ he says.

Nobody moves. We are frozen.

And then I hear it too. And then Latifa, and then Francisco.

A distant fly in a distant bottle.

Murdahhas either heard it, or believed that the rest of us have heard it. His chin has lifted from his chest, and his eyes are wide open.

But I can’t wait for him. I walk over to the parapet. ‘What are you doing?’ says Francisco.

‘This thing is going to kill us,’ I say. ‘It’s here to save us, Ricky.’

‘Kill us, Francisco.’

‘You fucking shit,’ screams Benjamin. ‘What the fuck are you doing?’

They’re all watching me now. Listening and watching. Because I have reached down to my little tent of brown grease-proof paper, and laid bare the treasures therein.

The British-made javelin is a light-weight, supersonic, self-contained surface-to-air missile system. It has a two-stage solid-fuel rocket motor, giving an effective range of between five and six kilometres, it weighs sixty-odd pounds in all, and it comes in any colour you want, so long as it’s olive green.

The system is made up of two handy units, the first being a sealed launch canister, containing the missile, and the second being the semi-automatic-line-of-sight-guidance system, which has a lot of very small, very clever, very expensive electronic stuff inside it. Once assembled, the javelin is capable of performing one job supremely well.

It shoots down helicopters.

That’s why I’d asked for it, you see. Bob Rayner would have got me a teasmaid, or a hair-dryer, or a BMW convertible, if I’d paid the right money.

But I’d said no, Bob. Put away those tempting things. I want a big toy. I want a javelin.

This particular model, according to Bob, had fallen onto the back of a lorry leaving an Army Ordnance depot nearColchester. You may wonder how such a thing can happen in the modern age, what with computerised inventories, and receipts, and armed men standing at gates - but, believe me, the army is no different from Harrods. Stock shrinkage is a constant problem.

The javelin had been carefully removed from the lorry by some friends of Rayner’s, who had transferred it to the underside of a VW minibus, where it had stayed, thank God, the course of its twelve hundred mile journey to Tangier.

I don’t know if the couple driving the bus knew it was there. I only know that they were New Zealanders.

‘You put that down,’ screams Benjamin. ‘Or what?’ I say.

‘I’ll fucking kill you,’ he yells, moving closer to the edge of the roof.

There is a pause, and it’s filled by buzzing. The fly in the bottle is angry.

‘I don’t care,’ I say. ‘I really don’t. If I put this down, I’m dead anyway. So I’ll hang on to it, thanks.’

‘Cisco,’ shouts Benjamin in desperation. ‘We’ve won. You said we’ve won.’ Nobody answers him, so Benjamin starts his jumping again. ‘If he shoots at the helicopter, they will kill us.’

There’s some more shouting now. A lot more. But it’s getting harder to tell where the shouting is coming from, because the buzz is gradually turning into a clatter. A clatter from the sun.

‘Ricky,’ says Francisco, and I realise that he is standing right behind me now. ‘You put it down.’

‘It’s going to kill us, Francisco,’ I say.

‘Put it down, Ricky. I count to five. You put it down, or I shoot you. I mean it.’

And I think he probably does mean it. I think he really believes that this sound, this beating of wings, is Mercy, not Death.

‘One,’ he says.

‘Up to you, Naimh,’ I say, adjusting my eye to the rubber collar on the sight. ‘Tell them the truth now. Tell them what this machine is, and what it’s going to do.’

‘He’s going to kill us,’ screams Benjamin, and I think I can see him leaping around somewhere on my left.

‘Two,’ says Francisco. I switch on the guidance system. The buzzing has gone, drowned out by the lower frequencies of the helicopter’s noise. Bass notes. Beating of wings.

‘Tell them, Naimh. If they shoot me, everybody dies. Tell them the truth.’

The sun covers the sky, blank and pitiless. There is only sun and clatter.

‘Three,’ says Francisco, and suddenly there’s some metal behind my left ear. It might be a spoon, but I don’t think so. ‘Yes or no, Naimh? What is it to be?’

‘Four,’ says Francisco.

The noise is big now. As big as the sun. ‘Kill it,’ says Francisco.

But it isn’t Francisco. It’s Murdah. And he’s not saying, he’s screaming. Going mad. He is ripping at the handcuffs, bleeding, shouting, thrashing, kicking grit across the roof.

And now I think Francisco has started shouting back at him, telling him to shut up, while Bernhard and Latifa scream at each other, or at me.

I think, but I’m not sure. They have all begun to disappear, you see. Fading away, leaving me in a very quiet world. Because now I can see it.

Small, black, fast. It could be a bug on the front of the sight. The Graduate.

Hydra rockets. Hellfire air-to-ground missiles..SO cannons. Four hundred miles an hour, if it needs to. One chance only.

It will come in and pick its targets. It has nothing to fear from us. Bunch of crazy terrorists with automatic rifles, popping away. Couldn’t hit a barn door.