Boundary (ฟ้าต่ำแผ่นดินสูง), a Thai-made documentary that screened in the Berlin festival's Forum section, has been banned.

The film follows the slow journey home of a Thai soldier who had been part of the government crackdown on the 2010 'red shirt' uprising and his arrival in the Thai-Cambodian border area, site of the disputed Preah Vihear temple.

It features YouTube footage of Thai and Cambodian soldiers fighting and a Cambodian soldier critical of Thailand.

"The Film and Video sub-committee [attached to the Ministry of Culture] do not permit the documentary film Boundary (Fah Tum Pandin Soong) to be screened in the Kingdom of Thailand.

The film's content is a threat to national security and international relations. The film presents some information on incidents that are still being deliberated by the Thai court and that have not yet been officially concluded," said Thailand's Film and Video sub-committee.