This article is more than 6 years old

This article is more than 6 years old

An international workers' union has declared the Thai government to be "on trial" in an impending defamation case against a British human rights defender who exposed alleged modern-day slavery in its canned fruit and fishing industry.

The International Transport Workers' Federation (ITF) has demanded that all charges against Andy Hall, 33, be dropped immediately, and described the trial – due in September – as "a national and international embarrassment".

Thailand's Natural Fruit Company filed civil and criminal cases against Hall earlier this year after he exposed alleged labour and human rights abuses, including violence against employees, forced overtime, the use of underage labour and the confiscation of passports of Burmese migrant workers.

He published his findings in a report called "Cheap has a high price" for the Finnish NGO Finnwatch in January last year and was hit with the libel suit one month later.

In May, separate defamation charges were filed by the same company over an Al-Jazeera interview about migrant workers' rights. Hall faces up to £5.8m in damages and a two-year prison sentence if found guilty.

The Thai government has defended the Natural Fruit Company and its case, saying the firm had a right to sue Hall and that he was allowed to defend himself under Thai law, according to FreshFruitPortal.com.

In a statement, the Royal Thai Embassy in London said it had "full confidence" in Thailand's judicial system.

A government inspection of the company premises reportedly took place a week after Hall's report was published. No instances of child labour were said to be uncovered. Finnwatch defended its research findings and wrote in a letter to the Thai ambassador to the UK, Pasan Tepara: "Thai officials' report states that there are undocumented workers working at the factory. According to Thai legislation, hiring undocumented migrants is illegal."

ITF's acting general secretary, Steve Cotton, said Hall should be "praised, not prosecuted" for his exposé on working conditions in the fruit company and added: "Thailand's attorney general must act now to disallow this case, which is an example of blatant victimisation of someone for no greater crime than telling an unacceptable truth."

ITF president Paddy Crumlin added: "Thailand itself is on trial. If ever a country needed to allow defenders of human rights to identify problems, it's this one."

Thailand was recently downgraded to the lowest ranking on the US government's human trafficking index for alleged rampant abuses in various industries including the fishing, construction and canning sectors.