A British academic who accused a Thai official of plagiarism, and whose name later showed up on a national security blacklist as a potential danger to society, said on Tuesday he had been freed after being held for four days at a Bangkok airport.

Pol Maj Gen Suvitchpol Imjairat, head of Immigration at Suvarnabhumi Airport, confirmed yesterday that a British academic Wyn Ellis was being held at the airport's detention centre because his name was officially blacklisted.