There is a further aspect to this incident I have just described which I hesitate to mention here, uncertain as I am that there is any substance to it. It has to do with Uncle Philip's manner that day as he tried to restrain my mother in front of our house; and again, something in his voice when he said as they came in: ‘But we have to pursue every possible avenue, don't you see?’ There was nothing at all concrete I could put my finger on, but then a child is sometimes very receptive to these less tangible things. Anyway, my feeling was that there was something definitely odd about Uncle Philip that day. I do not know why, but I got the distinct impression that on this occasion, Uncle Philip was not on ‘our side’; that the intimacy he shared with the plump Chinese man was greater than the one he shared with us; even – and quite possibly this was merely my fancy – that he and the plump man exchanged looks as the car drove off. As I say, I cannot point to anything solid to support these impressions, and it is more than possible I am projecting back certain perceptions in the light of what ultimately occurred with Uncle Philip.

Even today, I find it brings me some pain to remember the way my relationship with Uncle Philip concluded. As I have probably made clear, he had become over the years a figure to idolise, so much so that in the first days after my father's disappearance, I remember contemplating the notion that I need not mind so much since Uncle Philip could always take my father's place. Admittedly, this was an idea I found in the end curiously unconvincing, but my point is that Uncle Philip was a special person for me, and it is no wonder at all I should have lowered my guard that day and followed him.

I say ‘lowered my guard’ because for some time before that final day, I had been keeping watch over my mother with increasing anxiety. Even when she demanded to be left alone, I continued to keep a careful eye over the room she had gone into, and over the doors and windows through which kidnappers might enter. At nights I lay awake listening to her movements around the house, and always kept close to hand my weapon – a stick with a sharpened end Akira had given me.

However, when I think further about this, I have a feeling that deep down, I still did not at that stage truly believe my fears could be realised. Even the fact that I considered a pointed stick an adequate deterrent to kidnappers – that I often fell asleep fantasising I was locked in combat with dozens of intruders coming up our staircase, whom I would fell one by one with my stick – testifies perhaps to the oddly unreal level at which my fears still operated at that time.

For all that, there is no doubting the anxiety I felt for my mother's safety, and my bewilderment that the other adults had taken no steps at all to protect her. I did not like to let my mother out of my sight during this period, and as I say, I would never have lowered my guard on that day had it been anyone other than Uncle Philip.

It was a sunny, windy morning. I remember watching from the playroom windows the leaves blowing in the front yard over the carriage track. Uncle Philip had been downstairs with my mother since shortly after breakfast, and I had been able to relax for a while, believing as I did that nothing could happen to her while he was with her.

Then midway through the morning I heard Uncle Philip calling me. I went out on to the landing and, looking down over the balcony rail, saw my mother and Philip standing in the hall, gazing up at me. For the first time in weeks I sensed something cheerful about them, as though they had just been enjoying a joke. The front door was ajar and a long streak of sunlight was falling across the hall. Uncle Philip said:

‘Look here, Puffin. You're always saying you want a piano accordion. Well, I intend to buy you one. I spotted an excellent French model in a window in Hankow Road yesterday. Shopkeeper obviously has no idea what it's worth. I propose the two of us go and look it over. If it takes your fancy, then it's yours. Good plan?’

This brought me down the staircase at great speed. I jumped the last four steps and circled round the adults, flapping my arms in impersonation of a bird of prey. As I did so, to my delight, I heard my mother laughing – laughing in a way I had not heard her laugh for a while. In fact it is possible it was this very atmosphere – this feeling that things were perhaps starting to return to what they had been – which played a significant part in causing me to ‘lower my guard’. I asked Uncle Philip when we could go, to which he shrugged and said:

‘Why not now? If we leave it, someone else might spot it. Perhaps someone's buying it at this moment, even as we speak!’

I rushed to the doorway and again my mother laughed. Then she told me I would have to put on proper shoes and a jacket. I remember thinking of protesting about the jacket, but then deciding not to in case the adults changed their minds, not only about the accordion, but also about this whole light-hearted mood we were enjoying.

I waved casually to my mother as Uncle Philip and I set off across the front courtyard. Then several steps on, as I was hurrying towards the waiting carriage, Uncle Philip grasped me by the shoulder, saying: ‘Look! Wave to your mother!’ despite my already having done so. But I thought nothing of it at the time, and turning as bidden, waved once more to my mother's figure, elegantly upright in the doorway.

For much of the way, the carriage followed the route my mother and I usually took to the city centre. Uncle Philip was quiet on the journey, which surprised me a little, but I had never before been alone with him in a carriage and assumed this was perhaps his normal custom. Whenever I pointed out to him anything we were passing, he would reply cheerfully enough; but the next moment he would be staring silently once more out at the view. The leafy boulevards gave way to the narrow crowded streets, and our driver began to shout at the rickshaws and pedestrians in our path. We passed the little curio shops in Nanking Road, and I remember craning to see the window of the toy shop on the corner of Kwangse Road. I had just begun to anticipate the smell of rotting produce as we approached the vegetable market, when Uncle Philip suddenly rapped his cane to make the carriage stop.

‘From here, we'll go on foot,’ he said to me. ‘I know a good short cut. It'll be much quicker.’

This made perfectly good sense. I knew from experience how the little streets off Nanking Road could become so clogged with people that a carriage or motor car would often not move for five, even ten minutes at a time. I thus allowed him to help me down from the carriage with no argument. But it was then, I recall, that I had my first presentiment that something was wrong. Perhaps it was something in Uncle Philip's touch as he handed me down; perhaps there was something else in his manner. But then he smiled and made some remark I did not catch in the noise around us. He pointed towards a nearby alley and I stayed close behind him as we pushed our way through the good-humoured throng. We moved from bright sun to shade, and then he stopped and turned to me, right there in the midst of the jostling crowd. Placing a hand on my shoulder, he asked:

‘Christopher, do you know where we are now? Can you guess?’

I looked around me. Then pointing towards a stone arch under which crowds were pressing around the vegetable stalls, I replied: ‘Yes. That's Kiukiang Road through there.’

‘Ah. So you know exactly where we are.’ He gave an odd laugh. ‘You know your way around here very well.’

I nodded and waited, the feeling rising from the pit of my stomach that something of great horror was about to unfold. Perhaps Uncle Philip was about to say something else – perhaps he had planned the whole thing quite differently – but at that moment, as we stood there jostled on all sides, I believe he saw in my face that the game was up. A terrible confusion passed across his features, then he said, barely audibly in the din:

‘Good boy.’

He grasped my shoulder again and let his gaze wander about him. Then he appeared to come to a decision I had already anticipated.

‘Good boy!’ he said, this time more loudly, his voice trembling with emotion. Then he added: ‘I didn't want you hurt. You understand that? I didn't want you hurt.’

With that he spun round and vanished into the crowd. I made a half-hearted effort to follow, and after a moment caught sight of his white jacket hurrying through the people. Then he had passed under the arch and out of my view.

For the next few moments I remained standing there in the crowd, trying not to pursue the logic of what had just occurred. Then suddenly I began to move, back in the direction we had just come, to the street in which we had left the carriage. Abandoning all sense of decorum, I forced my way through the crowds, sometimes pushing violently, sometimes squeezing myself through gaps, so that people laughed or called angrily after me. I reached the street to discover of course that the carriage had long since gone on its way. For a few confused seconds I stood in the middle of the street, trying to form in my head a map of my route back home. I then began to run as fast as I could.

I ran down Kiukiang Road, across the hard uneven stones of Yunnan Road, pushed through more crowds along Nanking Road. When at last I reached Bubbling Well Road, my breath was already coming in gasps, but I was encouraged that I now had left only this one long straight road, relatively free of people.

Perhaps it was because I was conscious of the highly private nature of my fears – or perhaps some profound shift in attitude was already taking place within me – but it did not once occur to me to solicit help from any of the adults I passed, or to try and hail a passing carriage or motor car. I set off at a run down that long road, and even though I soon began to pant pathetically, even though I knew my gait must look appalling to an onlooker, even though the heat and exhaustion reduced me at times to little more than walking pace, I believe I did not stop at all. Then at last I was going past the American consul's residence, and then the Robertsons’ house. I turned off Bubbling Well Road into our road and a second wind took me the remaining distance to our gate.

I knew as soon as I turned through our gateway – though there was nothing obvious to tell me so – that I was too late, that the thing had finished long ago. I found the front door bolted. I ran to the back door, which opened for me, and ran through the house shouting for some reason not for my mother, but for Mei Li – perhaps even at that stage, I did not wish to acknowledge the implications of shouting for my mother.

The house appeared to be empty. Then as I was standing bewildered in the entrance hall, I heard a giggling sound. It had come from the library, and as I turned and went towards it, I saw through the half-open door Mei Li sitting at my work table. She was sitting very upright and as I appeared in the doorway, she looked at me and made another giggling sound, as if she were enjoying a private joke and trying to suppress her laughter. It dawned on me then that Mei Li was weeping, and I knew, as I had known throughout that punishing run home, that my mother was gone. And a cold fury rose within me towards Mei Li, who for all the fear and respect she had commanded from me over the years, I now realised was an impostor: someone not in the least capable of controlling this bewildering world that was unfolding all around me; a pathetic little woman who had built herself up in my eyes entirely on false pretences, who counted for nothing when the great forces clashed and battled. I stood in the doorway and stared at her with the utmost contempt.

It is now late – a good hour has passed since I set down that last sentence – and yet here I am, still at my desk. I suppose I have been turning over these recollections, some of which I had not brought to the fore of my mind for many years. But I have also been looking ahead, to the day when I eventually return to Shanghai; to all the things Akira and I will do there together. Of course, the city will have undergone many changes. But then I know Akira would like nothing more than to take me around, showing off all his great knowledge of the city's more intimate reaches. He will know just the right places to eat, to drink, to take a walk; the best establishments where we might go after a hard day, to sit and talk late into the night, swapping stories about all that has happened to us since our last meeting.

But I must now get some sleep. There is much work to be done in the morning, and I must catch up on the time lost this afternoon going about London with Sarah on the upper deck of that bus.