BANGKOK: Cambodia vows to defy Thai request for former PM amid deepening row between south-east Asian neighbours Thailand is stepping up its efforts to bring the fugitive Thai prime minister, Thaksin Shinawatra, to justice by preparing to demand his extradition from neighbouring Cambodia and considering new charges that could add a further 15 years to the two-year jail sentence he is already evading.

The billionaire, who was ousted from power in a 2006 military coup, flew into Phnom Penh yesterday in his private jet to take up a position as “economics adviser” to the Cambodian government.

Thailand and Cambodia have an extradition treaty. However, while Thailand says it will demand Thaksin be returned to serve his prison sentence over conflict of interest relating to a land deal, Cambodia is insisting he is a “political victim”, and refuses to arrest him.

Thaksin has added to the controversy by giving a newspaper interview, in which he allegedly criticises Thailand’s revered royal family. He is accused of calling for reform of the monarchy, and alluding to a “shining” new era in Thailand’s future.

Police have told this reporter they have transcripts of the interview, and are investigating after complaints from two senators. The crime of lese-majeste (insulting the monarch or treason) carries a 15-year jail term in the kingdom.

Thaksin’s new role as economics adviser to Cambodia — he will speak to 300 economists in Phnom Penh on Thursday — was offered to him by his self-declared “eternal friend” the Cambodian prime minister, Hun Sen. The relationship between the two men lies at the heart of the worsening row between the neighbours.

In recent days, as a war of words over Thaksin has escalated, both governments have withdrawn their respective ambassadors and Thailand has torn up an agreement over maritime boundaries. There is concern, too, that the long-running and violent dispute over the Preah Vihear temple on the countries’ shared border may flare up again. While the Thai government has promised to keep the border between the two countries open, tourism operators in Thailand are reporting that Thai holidaymakers have cancelled up to one in five trips to Cambodia.

The Thai prime minister, Abhisit Vejjajiva, said the letter demanding Thaksin’s extradition had been drafted and was awaiting a final detail. “We have to find exactly where Mr Thaksin is staying in Cambodia and how many days he will stay there. If the Cambodian government does not respond to our request, the foreign ministry will consider appropriate measures,” Abhisit said, declining to elaborate.

But the Cambodian foreign affairs spokesman, Kuoy Kong, said: “We will not extradite him [Thaksin]. We already clarified this case because he is a political victim.” Thaksin, who currently lives in Dubai, wrote on his website he was in Cambodia to discuss poverty and the world economic situation, but would defend Thai interests in Phnom Penh, “despite the Thai government still hounding me wherever I go”.

There is widespread speculation in the region Thaksin is plotting a political comeback. A base in Cambodia would make it easier for him to maintain contact with his supporters. The former prime minister, who won two landslide election victories before being pushed from power by the army, is still hugely popular in Thailand.