The Crown Prince is viewed with misgivings, after a tearaway youth that doesn't seem to have ended at 58. His behaviour continues to raise eyebrows, especially when a video circulated last year of a poolside birthday party for Foo Foo, at which his Royal Consort, Srirasmi, sat bare breasted. The monarchy has meanwhile become political ammunition in the battle between the ''Red Shirt'' supporters of the populist former telecom tycoon turned prime minister, Thaksin Shinawatra, and the ''Yellow Shirt'' backers of a more traditional elitism who wave the royal colours. Other US diplomatic cables from WikiLeaks suggest the royal house itself is also somewhat divided. Three of the most senior officials close to the king - the former prime minister Prem Tinsulanonda, the head of the Privy Council and a former army general, Anand Panyarachun, another former prime minister and air chief marshal Siddhi Savetsila - were quoted by the new US ambassador Eric John last January as saying they prefer the king's popular daughter, Princess Sirindhorn, as successor. The three elders were worried by Thaksin's cultivation of the Crown Prince, by paying off his debts and providing a luxurious new house in Bangkok. Vajiralongkorn preferred to spend time in Munich with his favourite consort, rather than with his official wife and children in Thailand, and had kept a succession of air hostesses as his mistresses. The ambassador quoted Anand as saying the Crown Prince would succeed his father according to the law, but there could be ''complicating factors'' if the prince proved unable to stay out of politics, or avoid embarrassing financial transactions.

"After a pause, Anand added that the consensus view among many Thai was that the Crown Prince could not stop either, nor would he be able, at age 57, to rectify his behaviour,'' John reported. But no one could raise ''such a delicate topic'' with the King. The revelations can't be discussed openly, but are causing turmoil. Thaksin was removed by military coup in 2006, tacitly backed by King Bhumipol, but his Red Shirt backers and his banned Thai Rak Thai party keep bobbing back. They are especially strong in the Thai rural hinterland, where Thaksin's extension of welfare broke an old pattern of patronage used by Bangkok elites. Abhisit Vejjajiva, appointed as Prime Minister in December 2008 with backing from the Yellow Shirts after some opaque Constitutional Court manoeuvres, wants to hold elections this year to reinforce his legitimacy. But there is no guarantee he will win. Meanwhile, authorities use a new computer crime law combined with an old lese majeste law to silence debate about the alleged misuse of royal power. Nearly 200 people have been arrested in the past four years, and lengthy jail terms of up to 18 years have been given. The atmosphere has darkened since the appointment of General Prayuth Chan-ocha as the new chief of the Royal Thai Army last October, when he declared the army's main purpose was ''protecting the country's sovereignty and the monarchy''. He followed up by warning that the army would intensify arrests for anti-monarchy postings by Red Shirts. ''Do not whine, because we have warned you many times,'' he said. ''From our grandparents' generation down to the present, we have been looked after by the monarchy, no matter which king.''

The political scientist Thitinan Pongsudhirak noted in the Bangkok Post this week that Prayuth was indicating ''internal challenges that he has not elaborated'' and ''may have unnecessarily drawn a line in the sand and defined the fault line of Thai politics around the monarchy.'' Prayuth had gathered around him in top posts his old colleagues from military academy and the 21st Infantry Regiment, known as the ''Queen's Guards'' (the Crown Prince being Queen Sirikit's favourite). Such concentrations have led to coups. This month's flare-up between Thai and Cambodian border troops over a disputed Hindu temple is also the result of Bangkok politics, according to Pavin Chachavalpongpun of Singapore's Institute of Southeast Asian Studies. Yellow Shirt activists crossed into Cambodian-held territory and got themselves arrested to create a nationalist wave for the election and paint Thaksin, who has been hosted during his exile by the Cambodian leader Hung Sen, as a traitor. Meanwhile, if at the Crown Prince's place, be careful about dogs. Chatting to the consort Srirasmi at the jazz dinner, US envoy Boyce recalled King Bhumipol talking animatedly to George Bush about his dog Thongdaeng. ''I mentioned having heard Princess Sirindhorn had a large dog, and I asked Srirasmi if she knew the breed,'' Boyce reported. ''Srirasmi appeared immediately to freeze up; her body language changed, and she said curtly that she knew nothing of Sirindhorn's affairs.'' Follow the National Times on Twitter: @NationalTimesAU