When Thai protesters recently set alight pictures of Ho Ching, chief executive of Temasek Holdings, it was a further indication that the Singapore state investment company was facing growing political problems as it expands across Asia.

The burning of images of Ms Ho and her husband Lee Hsien Loong, the Singapore prime minister, was part of protests in Bangkok over Temasek’s $1.9bn (?1.1bn) purchase of Shin Corp from the family of Thaksin Shinawatra, the Thai prime minister. Demonstrators are angry that the family used legal loopholes to pay no tax on the deal.