This was unexpected. I began to trot out some long-winded comments about the unusual nature of the project, how it was outside the mainstream of the centre’s work, and how I felt a degree of concern that we might all waste quite a lot of time and achieve nothing.

She listened patiently and then said, ‘Please call me Harriet. My surname is such a mouthful it really is too much to ask anyone to use it.’

I blushed. Perhaps Chetwode-Talbot has metamorphosed in pronunciation in the way Cholmondely has become Chumly, or Delwes Dales-one of those trick pronunciations invented by the English to confuse one other.

Then she suggested it might help if I understood some of the background.

I nodded; I needed to know who or what I was dealing with. Harriet-I don’t think it is appropriate for us to be on Christian-name terms, but it is quicker to write just her first name in this diary-began to explain. I crossed my legs and clasped my hands over my knees and generally tried to assume the expression my tutor at university used to adopt when I had put in a particularly bad piece of work which he was about to tear to shreds.

Harriet gave me a faint smile and explained that I had probably gathered by now that Fitzharris & Price were chartered surveyors and property consultants, not fisheries scientists.

I told her I appreciated the point.

She bowed her head in acknowledgement and explained that for many years the business of her office had been acquiring agricultural or sporting estates in the UK on behalf of overseas clients-in particular, Middle Eastern buyers. Fitzharris had discovered quite quickly that its clients didn’t just want it to buy the estates but also manage them in their absence.

That had led Fitzharris into providing technical expertise on a whole range of subjects, such as land agents’ services and help with recruiting estate employees through to advice on farming practice, sporting lets, obtaining planning permission for building new country houses, and so on.

Of course, Harriet told me, most of their clients are very wealthy, and are fond of often quite ambitious projects to improve the properties they buy. Then she said, ‘We have one such client who has been with us for a number of years. His wealth derives in part from oil, but if there is such a thing as a typical oil sheikh, he is not it. He is a most unusual, visionary man.’

Harriet paused to refill our cups with fresh coffee, and I found myself reluctantly admitting to myself that however foolish the project was, there was nothing foolish about this woman.

She added, ‘I am not going to attempt to describe what my client’s motivation is. I think it is important you try and understand it, if you decide to help us, but it is for him alone to tell you about that part.’ She continued, ‘He is a man we hold in great respect in this firm. He is an excellent steward and landlord of the properties he has bought in this country, an employer everyone would want to work for, but people like working for him because of his personal qualities and not because he is enormously wealthy. Moreover, he is an Anglophile, which is perhaps less usual in the Yemen than in some other parts of the region, and his prominence in his own country means he is viewed as a key potential ally in Yemeni councils by the Foreign Office here.’

‘Ah,’ I said.

‘Indeed, Dr Jones. I think you are aware there is a political dimension to all of this.’ She did not attempt to call me Alfred. ‘I know you will have had some pressure brought to bear on you from within government. Believe me, it was not of our doing and I very much regret it. We would rather you took on this job, impossible as it may seem at the moment, of your own free will, or else not at all. And that will certainly be the view of our client.’

‘Ah,’ I repeated, and then when she appeared to have stopped speaking, ‘Well. You were speaking about introducing salmon into the Yemen.’

‘And salmon fishing. I believe it is intended to be fly-fishing only, no spinning.’

‘No spinning,’ I repeated.

‘Are you a salmon fisherman, Dr Jones?’ asked Harriet. For some reason I blushed again, as if I was about to admit to something covert and slightly sinister. Perhaps I was.

‘As a matter of fact, I am very keen. Perhaps not as unusual amongst us fisheries people as you might think. Of course I nearly always put back any fish I catch. Yes, I enjoy it very much.’

‘Where do you fish?’

‘Here and there. I like to try different rivers. I’ve fished the Wye, the Eden and the Tyne in England; the Tay and the Dee and a few smaller Scottish rivers. I don’t get much time for it nowadays.’

‘Well, if you take this project on I’m sure my client will ask you to fish with him at his place in Scotland.’ Then she added with a smile, ‘And perhaps one day you’ll fish on the Wadi Aleyn, in the Yemen.’

I saw where this was going.

‘Well, there are a few problems with that idea,’ I suggested. This time Harriet crossed her legs, a movement that somehow caught my eye, and clasped her hands around her knees and looked at me critically, just as I had tried to do to her a moment or two earlier.

‘Let’s go through some of them,’ she suggested.

‘First, water,’ I said. ‘Salmon are fish. Fish need water.’ Harriet only looked at me when I said that, so I had to continue. ‘Specifically, as I said in my letter, salmon need cool, well-oxygenated water. The temperature should ideally not exceed eighteen degrees Celsius. The best conditions are rivers fed by snow melt or springs, although some varieties of salmon can live in lakes if they are deep and cool enough. So there’s a fundamental problem, right there.’

Harriet stood up and went across to her desk, took a file from it and then sat down again.

Opening the file she said, ‘Water. Parts of the Yemen have up to 250 millimetres of rainfall a month in the wet summer season. It is brushed by the monsoon, like parts of the Dhofar region in the south of Oman. On top of surface water run-off from the summer storms, there is constant recharging of the groundwater. People didn’t use to think there was much groundwater in the Yemen but since they started looking for oil they have found one or two big new aquifers. So, yes, water is a huge problem, but there is water there. The wadis become rivers, and pools and lakes form in the summer.’

This was surprising.

‘Then there is the question of water temperature. I suppose you’re going to tell me the Yemen isn’t that hot, but if it is, the oxygen will leave the water and the fish will die.’

Harriet looked at her file again and said, ‘We’re thinking mountains. That’s where the rain is, and the elevations in the central highlands go up to over 3000 metres. At that height the temperatures are bearable. The night-time temperatures go down to well below twenty Celsius even in the summer. And Pacific salmon get as far south as California -as long as the water is aerated, they seem to be able to survive. I don’t mean to be telling you your business, Dr Jones; just that it might not be as open and shut as you first thought.’

I paused, and then said, ‘Salmon parr feed off certain types of fly life, and if we introduced salmon from English rivers they would only recognise food that came from those rivers.’

‘Perhaps that can be introduced along with the fish? There are plenty of flies in the Yemen, at any rate. English ones might adapt if the local fly life didn’t taste good.’ She closed her file with a snap and looked at me with a smile.

‘Then,’ I said with mounting irritation, ‘the salmon parr grow up into smolts, and the smolts want to find the sea, and the particular part of the sea they want to find is just south of Iceland-at least if the fish broodstock comes from an English or Scottish river. How do you suppose these fish will get there? Through the Suez Canal?’