I looked at Pepe. His business made it unlikely that he had Communist Party connections. Probably the KGB had had Tiptree under observation when he came here to make arrangements about the money.

In such a situation almost everything is guesswork. I guessed the old man was the regular guard for the bank, simply because he did not look like the sort of tough whom Moskvin would bring in. And I guessed from the way he held the double-barrelled gun that Moskvin had removed the shells. And the despondent expressions of the faces of the young boys and the envy with which they eyed the machine-pistol convinced me that they were unarmed. I could take the old man and the kids, I could probably handle Moskvin at the same time, but the machine-pistol tilted the balance.

I kept my hands on my head and tried to look very frightened. It was not difficult, especially when I saw the way the kid with the machine-pistol was flourishing it and caressing the trigger lovingly. 'I want everyone to remain still,' said Moskvin. He said it frequently and in between saying it he was looking at his wrist-watch. 'And stay away from the windows.'

Pepe made a harmless move to get a handkerchief from his pocket. Moskvin was angry. He punched Pepe in the back with a force that knocked him to his knees. 'The next person to move without permission will be shot,' he promised, and gave Pepe a spiteful kick to emphasize this warning.

There were just the two of them, it seemed, and it was unlikely that they had worked together before. One machine-pistol and probably some kind of handgun in Moskvin's pocket. Against them, one person alone would stand little chance.

I looked round the room, deciding what to do when and if Stinnes pressed the buzzer. They'd have to open the door because otherwise the steel door-lining would both protect and hide him. Did they have someone downstairs in the bar, I wondered. Or someone outside in the street to watch for Stinnes's arrival. The crowded bar would make a perfect cover.

I looked at the three partners, the three guards and the two women clerks who'd been brought in from the next room. They all kept their hands on their heads, and they all had that patient and passive visage that makes the people of Latin America so recognizably different from the Latin people of Europe.

It was while I was musing on this question that I heard the bang of the downstairs door. Under normal circumstances the sounds of footsteps on the staircase would not have been audible, but the circumstances were not normal; everyone in the room was wound up tight.

The boy with the machine-pistol pulled the bolt back to cock the gun for firing. There was a dick as the sear engaged the sear-notch in the bolt. It was enough to snap some mechanism within Zena's mind. 'You promised,' she shouted. 'You promised not to hurt him.'

She was shouting at Moskvin, but he smiled without even bothering to look back at her. So that was how it had been done. Moskvin had been monitoring the whole thing through Zena. But she wasn't KGB material. There was no need to ask what she was getting out of it; the box of money. Nice going, Moskvin. But if my wife Fiona wasn't behind that notion I'd eat the money bill by bill.

We could hear the footsteps as someone reached the top of the stairs and paused on the landing. 'You promised,' said Zena. She was almost incoherent with anger. 'I love him. I told you.' She stiffened as she recognized their total indifference, and her face had gone livid under the bright make-up.

Neither Moskvin nor his machine-gun man bothered with Zena. Their eyes were on the door where Stinnes was expected any minute.

There is always some damned possibility that lies beyond every probability. Perhaps the only thing I'd never considered was that Zena could be infatuated with Stinnes. There was a strong streak of romanticism in her complex personality, and there was that old Prussian rectitude that made her record every broken teacup in a notebook. Zena would allow Stinnes to be betrayed but not killed.

Ignoring the machine-pistol, Zena flung herself across the room like a human cannon-ball. She collided with the boy, her feet kicking and fingernails gouging. He bent, and almost fell, under the momentum of her attack, and there was a crash as their two bodies smashed against the wall. Trying to defend himself against her fingernails, the boy dropped his machine-gun and tried to grab her hands. An ear-splitting bang echoed round the room as the bullet in the chamber was fired by the impact. But by that time Zena had her nails into the boy's face and he was yelling at her to stop. He was frightened of her, and it was to be heard in his yells. Thus encouraged, she stopped only long enough to grab his long hair and use it to swing his head against a sharp corner of a filing cabinet.

Had Moskvin reached into his pocket for a pistol, or stooped to pick up the machine-gun, he might have regained control. But he used his huge fists. It was the reflex action of a man who'd spent his life throwing his weight around both literally and figuratively. He gave Zena's small body a mighty blow to the kidneys and followed it with a left hand to the side of her head.

The punches landed with sickening force. They took care of little Zena all right. She was only half conscious as she fell to the floor, arms flailing. Then Moskvin could not resist a kick at her. But it took time. There was lots of time, and I pushed my pistol back into my belt as I watched Tiptree bring a small Browning automatic from his pocket and with commendable speed fire two shots at Moskvin. The first bullet went wild – I heard it ricochet and hit a typewriter in the next room – but his second bullet hit Moskvin in the leg. Moskvin stopped kicking Zena and screamed. I guessed he was an amateur. Now he demonstrated the way in which an amateur is efficient only while all goes well for him. Once injured, Moskvin lost interest in killing Stinnes. He lost interest in the money. He lost interest in the boy who'd had his face shredded by Zena's nails and his cranium gashed on the sharp corner of the filing cabinet. He even lost interest in the machine-pistol on the floor.

The Mexicans all remained very still, hands on heads and their faces impassive. I put my hands back on my head too. There was no sense in getting killed, but I got ready for the aftermath by stepping slowly to one side so that I could plant my foot on the machine-pistol. That was the trump card.

Moskvin fell back on to a chair and pressed his palm against the copious bleeding. He nursed his pain and wanted everything to stop. He clamped his hands to his wounded leg and crooned and wept with the pain of it. The pain could not have been very great but he was frightened. He'd probably convinced himself he was going to die. Even people hardened to the sight of blood can be very deeply affected by a glimpse of their own.

Now Tiptree found time enough to look around to see where I'd gone. 'Open the door,' he told me, with a superiority that bordered on contempt. 'And take your hands off your head. It's all over.' When I didn't move fast enough, he looked down to where I had my foot on the machine-pistol and said, 'Oh, you've got that, have you? Good.'

Loudly Moskvin said, 'I must go to hospital. I'm bleeding to death.'

'Shut up,' I said.

Despite the changed situation, the Mexicans kept their hands on their heads. They were taking no chances. I picked up the machine-gun, went to the door and slid back the hatch, expecting to see Stinnes. Instead, a small child whispered, 'I have a message. It is only for Senor Samson.'

'I'm Senor Samson,' I said.

The child looked at me for a long time before deciding to confide his very guarded message. He whispered, 'Your friend is waiting for you at the place you arranged.'

'Thank you,' I said.

'You are to give me one hundred pesos,' said the child. Stinnes knew how to get his messages delivered. I passed a note through the hatch to him, and then closed it.