A British academic, who exposed a Thai official who had plagiarised his work, is being held at a detention centre in Bangkok over allegations he is a threat to national security.

Officials at Bangkok Suvarnabhumi Airport stopped UN agricultural consultant Dr Wyn Ellis on Thursday 3 September,BBC News reported.

“I was told that I had been blacklisted as a danger to Thai society,” he told The Telegraph from the immigration holding centre.

“It’s ridiculous and I am hoping the immigration department will clear this up on Monday," he said.

The authorities attempted to deport Dr Ellis, who has lived in Thailand for 30 years, to Norway from where he arrived, but he refused to leave, according to The Telegraph.

His detention comes after Dr Ellis won a long-running plagiarism battle with the Thai government, which has raised questions about the country’s attitude towards intellectual property and whistle-blowers.

In 2008, Dr Ellis complained to Thailand’s elite Chulalongkorn University after he noticed that a dissertation submitted by Supachai Lorlowhakarn, the then director of Thailand's National Innovation Agency (NIA), had largely been copied from a report he had written for the country’s International Trade Centre.

However, Mr Supachai was allowed to graduate despite Dr Hunt’s plea that the PhD candidate had plagiarised his work.

The complaint was the start of a drawn-out legal battle which developed when the NIA filed nine lawsuits against Dr Ellis, including charges of criminal defamation, which can carry a prison sentence.

During this time, Dr Ellis received death threats, had his car’s windscreen was smashed with a large rock, and had his home monitored by the military.

Some two years after Dr Ellis made the complaint, the university investigated Mr Supacahai. Nut it wasn’t until 2012 – following an expose by the Times Higher Education magazine - that and he was stripped of his doctorate. He was later convicted of forging Dr Ellis’ employment contract.

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Seemingly bringing the legal battle to an end, Dr Ellis won seven of nine legal cases against him – two settled out of court – with the last case being dealt with by the Supreme Court in May 2014.

Dr Ellis had his wife, an academic who is a Thai citizen, are forced to live in a safe house under a witness protection scheme, The Telegraph reported.

However, the government continued to Mr Supachai until February 2015, and Dr Ellis later discovered that he the official told the Immigration Department to blacklist him in 2009, according to BBC News.

Dr Ellis is now waiting to be freed from a detention cell, despite an NIA letter which has retracted Mr Supachai‘s request.