I have heard it said that opium is unpredictable in its effects: although it makes most people torpid and silent, there are also some who become uncharacteristically loquacious under its influence. The truth of this was immediately demonstrated to me – for even as my own tongue grew heavy, Mr Chan seemed to become more communicative. I do not exactly know how it happened but suddenly he was talking to me about his journey to England, three decades before.

I listened to Mr Chan with my eyes closed, but not a word escaped me – except that after a while it was as if I were not listening at all, but actually seeing his narrative unfold before my eyes. Such are the miraculous powers of the drug that it was as if I had become a fifteen-year-old gardener called Ah Fey: there I was, on the deck of an East India Company ship, a lone Chinese boy, travelling westwards through the oceans, towards England.

My plant cases are as precious to me as life itself: I water them by day and sleep beside them at night; and when the weather grows hot, I build little huts over them, with my own sparse clothing; when we are beset by tempests and storms I shield them with my own body. At every turn the other crewmen do their best to thwart me. Some are lascars and some are English seamen, and they are often at each other’s throats: the one matter in which they are united is their hatred of me – to them I am little better than a monkey. When we cross the equator I submit tamely to their rituals – dunkings and daubings – but suddenly I find myself pinioned and spreadeagled on the deck. Then I hear a scraping sound: they are shearing off my queue with an unsharpened knife. I struggle at first, but then I realize that I am only making the pain worse; I lie still and let them finish – but I take note of who they are, and afterwards I plan my revenge. The ring-leader is a burly foretopman – late one night, during the dogwatch, when everyone is half-asleep, I make my way up to his foot-rope and scrape it thin. Two days later, in the midst of a gale, the rope snaps and he is lost at sea …

I arrive at Kew bringing with me more Chinese plants than anyone has succeeded in transporting before. These are plants that I myself have obtained for Mr Kerr in Canton: he has no more idea of where to find them than he has of buying opium – in all things I am his pander and procurer. But the successful delivery of the plants is attributed not to me but to Mr Kerr; I am but the monkey who travelled with them.