He looked stonily at me as I squatted beside him.

'How is it?' I asked.

He shrugged his shoulders. 'Not good,' he said breathlessly. He was sheet-white and his eyes were cloudy.

I said, 'Mark, thank you for saving Paula.'

'Don't thank me. That was my business.' He did not want to hear praise from me. 'I told you that man was off his rocker.'

'Well, he's out of it now. Ramirez too. Which leaves only you, Mark. And puts me in a devil of a fix.'

I expected his usual sneering retort, but instead he surprised me. He said, 'I know that, Mike. I've caused you a lot of grief, and I'm sorry. I'm likely to cause you a lot more as long as I live.'

'No, I'

'Which won't be long. I'm no doctor, but I know that much.'

'Mark, we'll be back in port pretty soon and you'll be in medical hands. We may even be sharing a ward,' I said, trying to speak lightly. Mark was sombre and less arrogant than I had ever known him, and I was dismayed.

'Don't be a fool, Mike,' he said with a touch of his old acerbity. 'You're going to have a million questions to answer as it is. It's not going to make things easier for you if you suddenly turn up with your long-lost, murdered, murderer brother, is it?'

I knew that he was right. I foresaw nothing but trouble for both of us. I shrank from the thought of turning him over to justice, but I could see no other way. Mark let me think about it for a while.

'Mike, I have one chance, just one, to make things easy for you. I've never done anything for you before. You have to give me this one chance.'

I said slowly, 'Dear God, what can I do?'

He pulled himself more upright and swayed a little. Then he said, 'Mike, I'm going to die.'

'Mark, you don't know'

'Hear me out.' His voice shook. 'Remember, Mike, I'm already a dead man. Without me you have every chance of coming clean out of this. There will be nobody to contradict your story. You were sailing to meet up with Ramirez on a survey expedition, and got caught up in the shambles of Falcon. By now the world will know it's blown. There'll be scientists overflying, ships coming to look, the lot. You know that. Your stalwart fellows can wipe out all traces of a gunfight. And you can persuade those Spaniards you've got on board to shut up.'

He drew in a harsh breath. He was drenching in his own sweat.

'Christ, do I have to spell it out for you? I'm not going to recover. I can do one thing for you, if you'll help me now.'

I asked, knowing the answer, 'Help you to do what?'

'Help me to die.'

I had known. 'Mark, I can't kill you.'

'You won't need to.'

Something glittered in front of my eyes. It was the kitchen knife Hadley had used on Mark, bloody at the tip but winking in the sunlight. I swallowed, a hard lump in my throat.

'What – do you want me to do?'

'Get me over the side, into the sea. It'll be as quick for me as it was for Hadley.'

Silently I got up and began to pace the deck. He watched me carefully, saying nothing, giving me time. This was the only completely unselfish thing he would ever have done in his life. But he gave me a dreadful choice.

At last I came back to him.

'All right, Mark. God forgive me, I'll help you.'

'Good.' He became brisk. 'Don't let anyone see us. The story will be that I climbed over on my own, after you'd gone. I would do that, but I need your help.'

There was nobody in sight. Geordie had done his work well.

I could find nothing else to say. Mark gave a short hard cough and his head drooped, and for an instant I thought that he had already died, sitting there. And then he raised his head and looked me in the eye. For the only time in my adult life our gazes locked without antagonism.

It took only a couple of moments. I got him over to the railing and we both looked down into the sea where the bow-wave ran along Esmerelda's side. I remember thinking how quiet it was.

He hooked one leg over the rail and I helped steady him as he lifted the other across. For an instant I held him.

'Goodbye, Mike,' he said clearly.

I let go. He fell backwards and disappeared into the spray. I turned blindly away and with my head in my hands huddled down by the side of the deckhouse.

After a while I stood up shakily. It was done. And I must go and talk to some of the crew. Not to Paula, not yet. But I must give Mark's plan a chance to work. I turned to leave.

The knife had gone from the deck.

I stood for a moment riveted, a flood of thoughts pouring into my mind. Then I swung round to look at the deck where Mark had been lying. There was still no knife, and now that I came to think of it, very little blood.

In two strides I was at the rail, looking aft, my thoughts erupting as the volcano had done. The motor launch which had been running in tow was gone, and the painter dangled loosely over the stern. Across the water I thought I could see a ' tiny dancing speck, but I couldn't be sure of that, or of anything.

Slowly I walked aft and hauled in the painter. The end of it had been cut across, newly-severed and just beginning to fray.

There was fuel in the launch and iron rations, for it had always had the function of a lifeboat. There were fishing lines, blankets, flares, a first aid kit. There was everything needed for survival.

I stood at the railing, alone as I'd asked to be, and bade my brother a final, ironic farewell. And yes, I wished him luck.