Hun Sen embraces Thaksin Shinawatra during a meeting in Phnom Penh in December 2009.

CAMBODIA and Thailand were nearing a resolution over the disputed oil blocks in the Gulf of Thailand just as Thaksin Shinawatra was ousted from office in 2006, a US embassy cable revealed yesterday.

The cable, dated May 15, 2007, details the visit of the US-ASEAN Business Council to Phnom Penh. During meetings with high-ranking officials, the cable states that representatives from US energy giant ConocoPhillips urged the government “to resolve the dispute with Thailand over the Overlapping Claims Area in the Gulf of Thailand. Noting that their firm has held a contract for exploitation of the area for nearly ten years”.

During the meeting, however, Secretary of State at the Ministry of Foreign Affairs Kao Kim Hourn told the company that “the two governments had come very close to settling the dispute just prior to the fall of the Thaksin government in Thailand,” the leak stated.

“He said they had agreed on a formula for dividing the revenue: 80% for Thailand and 20% for Cambodia in the tier nearest Thailand, 50%-50% in the middle and 20% for Thailand and 80% for Cambodia in the area closest to Cambodia,” it added.

“He thought that an additional six months of negotiations would have settled the matter,” the document said.

The importance of the overlapping claims area for the future of the region was underlined in another leak released yesterday detailing a 2007 meeting with Chevron’s General Manager for Exploration Gary Flaherty.

The cable said that Chevron, the developer of Cambodia’s off-shore block A, was most interested in gaining rights to a block in the overlapping claims area with Flaherty saying that the OCA was “one of the best areas for exploration in the world” and it could “revolutionise Cambodia”.

Block A, however, was “not significant enough to make exploitation of that block alone profitable”.

Following Thaksin’s removal, the issue of overlapping claims has made little progress and Thaksin’s 2009 appointment as economic advisor to Cambodia caused further problems when the Thai cabinet moved to cancel a memorandum of understanding agreed with Cambodia in 2001, claiming that new role undermined Bangkok’s negotiating position.

The leaked documents also shed light on the relationship between the ousted Thai prime minister – whose sister won a national election in Thailand this month – and Cambodia. In a cable in December 2009, a visit to Phnom Penh by Thaksin was seen by most observers as “a continuation of Hun Sen and Thaksin using each other for personal gain”.

Men Den, deputy director of Cambodian National Petroleum Authority, said yesterday that: “I did not know about the agreement for dividing revenue of oil between Cambodia and Thailand and it is beyond my responsibility.”

Keo Kim Hourn said that “he didn’t remember”.

Chevron declined to comment last night.