Prateep said yesterday he would appeal to the Central Administrative Court, and consider taking the case to the Criminal Court at a later stage.

After sailing easily through most stages of the three-month selection process, Prateep was found to be the only qualified candidate for the post of secretary-general at the NHSO board meeting on July 4.

Yet the board voted 14 to 13 against his endorsement.

“The board’s decision to not endorse me is illegitimate,” Prateep said, pointing out that he was declared to be the only eligible candidate in the selection process that began on April 4.

He also questioned the procedure used in counting votes at the board meeting.

The NHSO board’s decision has also been criticised by many high-profile figures in the public health sector, who said they suspect that “someone” plans to drastically overhaul the universal healthcare system, which has been managed by the NHSO over the past 14 years.

Covering nearly 49 million people in Thailand, the scheme offers most medical services for free to beneficiaries. However, studies have recommended that a co-payment system should be introduced to prevent the scheme from collapsing.

Prateep, who earned the backing of rural doctors and many non-government organisations, yesterday pledged to continue supporting the founding principles of the scheme, reflecting his intention to prevent major changes from being made.

Pin Nantasen, president of the Health Professional Association, said yesterday that the NHSO had made a mistake in deciding not to endorse Prateep.

“He is truly dedicated to developing the scheme,” he said.

Saichon Soratat, who leads a |network of cancer patients, said |her group would file a petition with Prime Minister Prayut Chan-o-cha via the Office of the Public Sector Development Commission tomorrow.