By Rachel Harvey
BBC News, Bangkok
Jetsun Pema was due to give a speech called Tibet: My Story
Thailand has refused to grant a visa to the sister of the Dalai Lama because it does not want to anger China.
Jetsun Pema, younger sister of the Tibetan spiritual leader, was due to be giving a keynote speech at a festival of Tibetan culture in Bangkok
But the Thai Foreign ministry said her visa request was denied over fears her presence could be linked to politics.
China regards Tibet as an integral part of its territory, and considers the Dalai Lama a dangerous separatist.
About 30 Tibetan exiles living in India have been granted visas to take part in the Festival of Tibetan Spirituality, Arts and Cultures, which gets under way in the Thai capital on Friday.
But the guest of honour is missing from the list.
Jetsun Pema, the 69-year-old sister of the Dalai Lama, was supposed to be giving a speech, with the working title Tibet: My Story.
But the Thai government has decided that telling her story could be interpreted by China as a political statement.
A spokesman for the Thai Foreign Ministry told the BBC: "Thailand has a long-standing policy of not letting any person use Thailand as a base to criticise or undertake activities detrimental to other countries."
The growing trade between Beijing and Bangkok may also have been a factor.
Ironically, in trying to avoid a potential diplomatic spat, the Thai government may well have injected into the cultural festival the very element of politics it was trying to avoid.