It was a bolt from the red, white and blue. A few weeks ago the youngest daughter of Thailand’s ageing king posted several photographs of herself on social media. One of them showed her with hair braids of red, blue and white; another of her wearing a similarly-striped bracelet. These are the colours of Thailand’s national flag, but they have also come to be associated with the anti-government protesters who have rocked the country as they seek to oust Prime Minister Yingluck Shinawatra.
Whether or not it was her intention to do so, the posting of the images by Princess Chulabhorn Mahidol was widely interpreted as a sign of her support for the anti-government forces.
"It was seen as a declaration of war," said a Thai political analyst sympathetic to the government, who asked not to be named. "Her doing that gave a symbol that elements within the palace support this protest 100 per cent."
The furore has drawn attention to an issue that is rarely discussed in public, but which some say is crucial to understanding what is happening in Thailand.
While the conflict is fuelled by several factors, say those analysts, the declining health of 86-year-old King Bhumibol Adulyadej and the behind-the-scenes jostling for position ahead of his succession is a major driver of the turmoil playing out on the streets of Bangkok.
Some consider it nothing less than the fall-out of a dynastic battle in which the children of the king have taken different sides.
"The old elites have never cared about democracy. But when the king dies they want to be sure that they control the parliament," said Andrew MacGregor Marshall, a journalist and author of an upcoming book on Thailand titled A Kingdom in Crisis.
According to the rules of succession, on the death of the king the throne should pass to Crown Prince Maha Vajiralongkorn. But within the palace establishment - the network of privy counsellors, advisors and minor royals - are those who would prefer it instead went to Crown Princess Maha Chakri Sirindhorn. Princess Chulabhorn, who posted the images on Instagram, is said to be an ally of the Crown Princess.