Pineapples - the centre of the controversy over Andy Hall's report flickr

Andy Hall, a British rights activist with Migrant Worker Rights Network has been found guilty of criminal defamation and computer crimes by a court in Thailand over a report published three years ago on alleged labour abuses at a large pineapple wholesaler.

Hall was initially given a four years' suspended prison sentence but this was cut to three years' "due to his history of doing public good and his record as a rights defender," the presiding judge said.

Hall had helped author a report published in 2013 for Finnwatch, a Finland-based watchdog group.

The Bangkok South Criminal Court, in its ruling said that Hall failed to interview a large enough sample size for his report for Finnwatch. It also said that investigations by state auditors did not find the widespread abuses alleged at Natural Fruit Company. The court also found that Hall had failed to give the company sufficient time to respond before submitting the report entitled 'Cheap Has a High Price' to Finnwatch.

The report, which alleged labour abuses at a processing plant in Prachuap Khiri Khan province, owned by the company, led to several firms terminating their contracts with Natural Fruits.

Finnwatch says shocked by court's findings

In a statement, Finnwatch said: "We are shocked by today's verdict. The report was authored and published by Finnwatch; we take full responsibility for it. Andy has been made a scapegoat in order to stifle other voices that speak out legitimately in support of migrant worker rights."

Sonja Vartiala, Finnwatch's Executive Director added: "This is a sad day for freedom of expression in Thailand. We fear that many other human rights defenders and victims of company abuse will be scared to silence by this ruling."

Finnwatch said that Thailand's laws that allows criminal punishment and imprisonment for defamation are "in clear breach" of the country's international human rights obligations. It said Thailand should focus on the allegations of violations of migrant workers' rights instead of pursuing the court case against Hall.

Natural Fruit has also filed two civil claims for damages against Hall seeking a total of around €10m. Both cases have been put on hold pending the criminal defamation case, Finnwatch said.

Hall, Finnwatch said, is expected to travel to Finland on Thursday 22 September for talks with Finnish companies and the media.

Separately, Hall, who said he will appeal the verdict, said he still stands by his research. He accused the company of trying to detract from the report's damning findings through this legal action.

Natural Fruit accuses Hall of violating company's rights

Meanwhile Natural Fruit's President Wirat Piyapornpaiboon accused Hall of "violating his rights." He said: "No foreigner should think they have power about Thai sovereignty."