The evidence of the Thai army's involvement in a secret programme to abandon migrants and refugees from Myanmar and Bangladesh at sea is now beyond question. It is clear from the interviews and photographs presented by this newspaper over the past week that appalling violations of human rights have been committed. While hundreds of people are known to have perished in the past month, the fate of another 46 who arrived over the past week and are in custody is in the balance. With thousands more expected to leave Bangladesh in coming weeks, a tragedy on an even more atrocious scale is in the offing if the policy continues. That new prime minister Abhisit Vejjajiva and his government have recognised the seriousness of the matter and heeded our call for action is therefore welcome. Mr Abhisit assured human rights groups yesterday that there would be a thorough investigation. Foreign Minister Kasit Piromya announced officials would meet envoys of Myanmar and the other countries involved in the issue of the boatpeople - Malaysia, Indonesia, Bangladesh and India - to find a solution. This is without doubt a good sign; previous Thai administrations, particularly that of former prime minister Thaksin Shinawatra, more often than not rode roughshod over the rights of citizens and refugees. The urgent effort that has been promised has to be faithfully delivered. Harsh treatment of asylum seekers in Thailand is nothing new. But the manner in which the people from Myanmar's Rohingya ethnic minority have been dealt with is especially harrowing. Myanmar's military rulers have for decades persecuted the Rohingyas. They have denied them citizenship, refused to allow them the right to practise their Muslim faith, confiscated their land and property and pushed them into forced labour. Hundreds of thousands have fled the country since the policy began in 1978. Many have gone to neighbouring Bangladesh, where they are held in refugee camps; others have headed for a perceived better life in Thailand, India and Muslim-majority Malaysia and Indonesia. Thailand is known as the land of smiles, but there were only distressing times for the 1,000 people from Myanmar rounded up by the Thai army on the country's western shores last month. They were set adrift with little food on rickety craft that were towed out to sea. Their chances of survival were limited, and more than half are either dead or still missing. Thailand is not party to international rules that guarantee the rights of refugees and its actions are beyond the pale. This situation cannot continue. The investigation must be carried out with the utmost urgency so that there can never be a repeat. A long-term solution to the plight of the Rohingyas has to be formulated by the governments involved. There can be no turning back from the new course now open to Mr Abhisit.