Long flight home, during which I finished Sarah Rose's For All the Tea in China, which is not so much a book about the origins of tea, but how Britain switched from buying it from China to growing it in India.
For years the importing of tea was financed by the exporting of opium. But tea was expensive and the bartering with opium was 'problematic', though it didn't stop Britain waging two wars to try and perpetuate it. Around the mid 1800s someone in the East India Company thought it would be a good thing to grow its own tea in India, in Assam and Darjeeling where the conditions were just right. It would improve the Company's balance of trade. The problem was, India had no tea plants worth growing and no-one really knew what to do with them if it had.
So, the Company sent a botanist called Robert Fortune to China to learn the secrets of tea growing, take seeds & cuttings and transport them to India. Tea espionage. He dressed as a mandarin with fake queue and went into the mountains of East China where no other European had penetrated. And that's how tea came to be grown in India.