Henri George Kennedy was a Student Interpreter at the British Consulate in Bangkok when he met pioneer photographer J. Thomson and went with him in his famous travel through Cambodia in January-May 1866.
Fluent in Thai (Siamese), H.G. Kennedy is credited to have saved Thomson's life when the latter contracted high fever during the journey. While several French officials in Cambodia suspected him to be a British spy, it seems that Kennedy, then a young expatriate, was merely attracted by the adventurous travel.
However, Jim Mizerski noted in Cambodia Captured: "Given the unresolved political scenario in Southeast Asia at the time, it is not unlikely that Kennedy's participation involved more than just accompanying Thomson. lt was an opportunity for Great Britain to get a good look at Angkor and a better assessment of the French in Cambodia while still maintaining the pretext of being little more than a tourist. Kennedy was likely collecting intelligence, but in plain sight and with deniability due to his authentic position as a junior interpreter. He later wrote a paper about the trip for the Royal Geographical Society of London that was accepted and published. His report to his superiors in Bangkok probably included more information than was included in the R.G.S.L. paper."
The British mission in Bangkok had been established in 1856, in a building on Charoen Krung Road by the Chao Phraya River that became the UK Embassy in 1947, until its demolition for urban development in 2017.