A British journalist with the BBC faces up to five years in a Thai jail after a lawyer brought a criminal defamation case against him over an investigation into fraud on a popular tourist island.

Rights groups say the case is the latest example of how Thailand's broad defamation and computer crime laws shut down investigative journalism and make it difficult to expose wrongdoing in a country where corruption is endemic.

The prosecution was sparked by a September 2015 report by Jonathan Head, the BBC's Southeast Asia correspondent, looking at how two foreign retirees were scammed out of their properties in Phuket.

Head is due to appear in a Phuket court today alongside one of the retirees, British national Ian Rance who is a joint defendant in the prosecution, to enter their plea.

The man bringing the prosecution is Pratuan Thanarak, a Phuket lawyer who featured in the BBC's report looking at how Rance lost lucrative properties.

Rance retired to Phuket in 2001, married a local woman with whom he had three children and bought what he said were some 1.2 million worth of properties.

Under Thai law foreigners cannot own land. But many get around that provision by placing properties in the name of a company they own or with locals they trust.

In 2010 Rance discovered his wife had forged his signature to remove him as director and sell the properties with the help of a network of money lenders and property agents on the island.

She was jailed for four years over the scam.

The BBC's Head reported that Pratuan, the lawyer, admitted to notarising Rance's signature without him being present.

Pratuan filed a defamation case alleging the reports caused him to be "defamed, insulted or hated", according to a copy of the complaint seen by AFP.

Rance and Head face one charge of criminal defamation, which carries up to two years in jail. Head faces an additional charge under Thailand's Computer Crimes Act, which has a five year maximum jail penalty.

Head has had to surrender his passport to the court leaving him unable to work across Asia as he fights what is likely to be a two year court battle.

In a statement the BBC said it "stands by its journalism" and that they "intend to clear the name of our correspondent".