The dispute along the Thai-Cambodian border in the Preah Vihear temple area could develop into a heated conflict among Thais if the International Court of Justice's clarification on the case does not favour Thailand, former prime minister Thaksin Shinawatra has warned.
The government, under the premiership of his younger sister Yingluck, will have to work very hard to explain the facts about the issue and Thailand's justification for its position, he said.
Thailand and Cambodia have been engaged in a dispute over the sovereignty of 4.6 sq km around the temple in Si Sa Ket province. The issue caused conflict between the countries when Cambodia applied to register the temple as a world heritage site with Unesco in 2009.
The Thai government, then under the premiership of the late Samak Sundaravej, supported Cambodia's application. That led to the Cambodian government demanding to develop the temple and the 4.6 sq km area to meet the World Heritage Commission's requirements.
However, the Samak government's move was strongly opposed by certain groups, including the opposition Democrat Party.
Thaksin, in a recent interview with the Bangkok Post, admitted that Noppadon Pattama, the foreign minister at that time, should not have supported Cambodia's application.
''Frankly speaking, Thailand is at a disadvantage in this case,'' he said.
He recalled an event more than a century ago when the then minister of interior, Prince Damrong Rajanuparb, who was the younger brother of King Rama V, visited Preah Vihear temple.
Thaksin said the prince was welcomed by officials from France, which had colonised Cambodia, at the top of the hill where the temple was located.
''The French raised the Cambodian national flag on the hill and then presented a map to Prince Damrong Rajanuparb. Our prince did not express any objection to the map. Instead, he asked for five more copies of the map to be given to Thai authorities to use,'' Thaksin said.
Under international practice, if a country disagrees with the border line in a map drawn by a neighbouring country, it must object to the map and hold talks with the other country to settle the disagreement.
But in this case the Thai side did not object to the map presented by the French and that was interpreted as an acceptance of the border details.
This led to Thailand losing out in a dispute in 1962 when the International Court of Justice ruled in favour of Cambodia over the Preah Vihear issue.
However, the court ruled only that the temple was under the sovereignty of Cambodia without clarification.
''Therefore, sovereignty over the 4.6 square kilometre area near the temple was unclear,'' Thaksin said.
When he was prime minister, Thaksin said the area was occupied by Cambodian vendors, so he held talks with the the country's government, proposing that the area be declared a ''no man's land'' until a joint agreement over sovereignty was made.
Thaksin also recalled that he had offered his Cambodian counterpart a joint development plan for the area to make it a tourism spot.
But before an official treaty could be signed, his government was toppled in the Sept 19, 2006 coup.
After then foreign minister Noppadon Pattama provided his support to Cambodia's application, the next government, led by the Democrat Party, highlighted the issue and that prompted the Cambodian side to take the issue to the International Court of Justice, asking for a clarification of its verdict in 1962, Thaksin said.
He said he was afraid the clarification was not likely to be in Thailand's favour.
''And I fear that the issue could develop into a deep rift among Thais as it concerns the country's sovereignty,'' Thaksin said.
He urged the government to work hard to explain the facts of what happened in the past to the public so as to avoid serious conflict.
Although his sister's government has improved the relationship with Cambodia, it is unlikely to ask Phnom Penh to withdraw the case from the International Court of Justice.
''If the Cambodian government agreed to withdraw the case, then it would face a political crisis as the Cambodian people would strongly oppose their government,'' Thaksin said.
He said the government could try to prolong the case as long as possible if tensions rise again.