He looked at me for a long time and then said gently, 'And on the basis of this you want me to invest maybe a million dollars.'

I got out of my chair.

'Sorry to have wasted your time, Mr Campbell.'

'Sit down, you damned fool. Don't give up without a fight. I haven't said I won't invest, have I?' He saw the look on my face and added, 'And I haven't yet said I will, either. Have you got that diary here?'

Wordlessly I took it from my breast pocket and handed it over the desk. He flicked it open and turned rapidly from page to page. 'Who taught your brother to write shorthand?' he asked disgustedly. 'St Vitus?'

'Basically it's Pitman's,' I said. 'But Mark adapted it.' I could have gone on to say that Mark had always been secretive, never liking anyone to know what he was doing. But I kept my mouth shut.

Campbell tossed the diary aside. 'Maybe we can get something out of it somehow – maybe a cipher expert can sort it out.' He turned in his swivel chair and looked out of the window towards Hyde Park, and there was a long silence until he spoke again.

'You know what really interested me in this improbable story of yours?'

'No, I don't.'

'Those South Americans,' he said unexpectedly. 'South America has been unlucky for me, you know. I lost nearly ten million down there. That's when Mark's expedition went down the drain, along with a lot of other things. And now Mark has come back – in a sense – and more South Americans are involved. What do you make of that?'

'Not a thing,' I said.

'I don't believe in coincidence. Not when it happens like this. What I do have to consider lies outside your domain, perhaps – the complications of international law regarding mining, especially offshore, undersea stuff. International relations – so I have to know more about the areas you want to research. Financing. Distribution. Markets.'

I was a little taken aback. Perhaps I was too much of the research scientist – the hard facts of commercial dealing had hardly occurred to me. But on reflection I could hear no note of doubt or dismay in Campbell's voice, only the sound of a man mulling over the forthcoming ramifications of the deal he was being offered – and liking it. There was undoubtedly the faint note of challenge in his attitude, and this encouraged me. I guessed that he, like Geordie's old pal Ian Lewis, may be finding life a little boring at present and was attracted by the novelty of my proposition.

He poked the nodule with his finger. There are two things necessary for industrial civilization – cheap power and cheap steel. What's the iron oxide content of this?'

'Thirty-two per cent by weight.'

That does it. The cobalt will make it economically feasible and the result is a cheap high-grade iron ore, a hell of a lot of manganese, plus some copper, vanadium and anything else we can pick up. Cheap metals, billions of dollars' worth and cheaper than anyone else can produce. It can be tied into one neat, strong package – but it needs careful handling. And above all it needs secrecy.'

'I know. I've already been stalling off a police inspector who thinks there's more to the burglary than meets the eye.'

Campbell appeared satisfied. 'Good. You've got the point.'

Then you're willing to finance an expedition?' I asked. It was almost too easy, I thought, and I was right.

'I don't know yet. I want to make some investigations of my own, enquiries which I can make and you can't. And maybe I can find Kane for you. Besides, you may not be in a position to undertake anything for some time – you killed a man, remember.' His smile this time was more grim than charming. 'Not that I blame you for it – I've killed men myself- but let's wait for your inquest before deciding anything.'

It was six days to the inquest, the longest six days I've spent in my life. To fill in the time I got down to writing the paper that I was supposed to turn out. It wasn't a very good paper as it happened; I had too much else on my mind to concentrate really well.

By the end of the week Geordie still hadn't found Kane, though he'd got a lot of other things moving. 'It's hopeless,' he said to me. 'A needle in a haystack would be easier- this is like trying to find one particular wisp of hay.'

'He may not be in London at all.'

A truism which didn't help. But on the morning of the inquest Kane was found – or rather, he found me.

He called at the flat just as I was leaving for the court -Geordie as usual was out ahead of me and would meet me there. Kane was looking a little the worse for wear with bloodshot eyes and a greying stubble on his cheeks. He coughed raspingly and said, 'Sorry to trouble you, Mr Trevelyan, but you did say I was to keep in touch.'

I looked at him in astonishment and choked back the questions that were on the tip of my tongue. I invited him inside and did a bit of fast thinking as I poured him a cup of coffee. Geordie and Campbell had as much at stake in this as I had, and besides I wanted witnesses when I questioned Kane. I decided to play it softly, though I could hardly bear to speak to him without losing my control.

I made myself smile pleasantly at him. 'Had enough of England, Mr Kane?'

'It 'ud be a nice country if it wasn't for your bleeding weather. We could do with some of this rain back in Queensland, my word.'

'But you've enjoyed your stay?'

'I've had a bonzer time,' he said. 'But my stay's over, Mr Trevelyan. I got to gambling again. I'll never learn.'

'I'm sorry to hear that,' I said.

He looked at me hopefully. 'Mr Trevelyan, you said you might be able to arrange a passage for me. I wondered…'

'Do you have to get back to the Pacific immediately?'

For some reason that didn't please him. 'Not specially, no. But I've got no boodle. If I had some cash or a job I'd like to stay around a bit. I thought maybe you could…'

I said, 'I have a friend who has a yacht which he's fitting out. He and I hope to get in some sailing together, and I think he needs crew. How would that suit you?'

He took the bait eagerly. 'That 'ud be just fine, Mr Trevelyan!'

I put an opened writing pad in front of him, trying to hold back my own eagerness. 'Write down the name of wherever you're staying so that I can get the owner to contact you,' I said. 'He'll want to interview you but I'll make it all right with him. And I'll let you have something ahead of your pay, to cover your rooming costs. How's that?'

He wrote an address down. 'I'll do that. Thanks a whole lot, Mr Trevelyan.'

'That's all right,' I said generously. 'You've earned it.'

I gave him a head start and then left for the court hearing. The encounter had been good for me, giving me something else to think about and making a vital connection in my story for Campbell. I had no time to tell Geordie about it, however, but savoured telling him afterwards.

The inquest was simple and straightforward. A doctor gave evidence of death, then I went on the stand, followed immediately by Geordie. We stuck to straight facts and didn't elaborate but I noticed that Geordie kept his bandaged finger prominently in view of the coroner. My neighbour spoke and then the police had their turn.

As Geordie was giving evidence I glanced round the courtroom and saw Campbell sitting at the back. He nodded to me, then turned his attention to the proceedings.

The Inspector made an appearance and confirmed that he had found a gun, a Beretta automatic pistol, hanging from the right-hand coat pocket of the deceased. The foresight was caught in the torn lining. I felt a lot better after this because it had been one of the points I had made myself. I looked the coroner straight in the eye and he didn't avoid my glance – a good sign. The lack of identity of the dead man was briefly discussed.