A factory worker in Thailand who is facing up to 37 years in jail for insulting the military rulers is also being investigated for mocking the king’s dog.

Strict lèse-majesté laws in Thailand make it a crime to criticise, defame or insult members of the royal family, and can land people in jail for up to 15 years on each count.

Thanakorn Siripaiboon was charged by a military court with making a “sarcastic” internet post about Tongdaeng, or Copper, a much-loved street mongrel rescued by King Bhumibol Adulyadej from an alley.

Praised for her loyalty and obedience, Tongdaeng is a household name. The king wrote and illustrated a book about her in 2002 and an animated film this year, Khun Tongdaeng: The Inspiration, is second in the box office. “Khun” is a Thai term of respect.

A poster for Khun Tongdaeng: The Inspiration at a cinema in Bangkok. The animated film is based on the Thai king’s favourite dog. Photograph: Nicolas Asfouri/AFP/Getty Images

Thanakorn’s lawyer, Anon Numpa, told the International New York Times that the military had not detailed the precise insult towards the animal.

“I never imagined they would use the law for the royal dog,” he said. “It’s nonsense.”

So sensitive is the topic that the local printer of the International New York Times in Thailand refused to publish an article on the dog on Tuesday, instead leaving a blank space where the story should have appeared.

With shrinking space for any discussion of those in power in the south-east Asian nation, this is the fourth time this year the printer has refused to publish International New York Times articles on Thailand, including once for a story that simply discussed the flagging economy.

Our Thai printer blocked publication of article about man charged with defaming king's dog. https://t.co/NAi7gQlfYx pic.twitter.com/X7iaIOg5ny — Thomas Fuller (@thomasfullerNYT) December 14, 2015

Lèse-majesté (injured majesty) convictions have surged since Thailand’s arch-royalist generals seized power from the elected government in May 2014. One man was jailed this year for 30 years for insulting the monarchy on Facebook.



It is not clear if the uptick in cases comes from the palace or the government, which has cracked down on dissidents by detaining academics, journalists and politicians for “attitude adjustment”, a programme the junta uses to interrogate opponents.

Thanakorn was also charged with sedition last week for sharing on Facebook allegations of corruption in the military’s construction of a park monument. He was held incommunicado until Monday.

While the junta uses lèse-majesté against critics, many Thais look back to a time where the king himself encouraged dissent, including during his 2005 birthday speech when he said he should be criticised as he is human.

Bhumibol, now 88 and the world’s longest-serving monarch, has wielded much influence since the closing days of the second world war and is seen as a important balancing figure in a country where political divides often result in bloodshed and revolt.

But with the king in poor health, there is country-wide anxiety over both the future transfer of the throne to the crown prince and the current widening crackdown by the army, which has promised a vague two-year timeframe for a return to democracy.

The recently arrived US ambassador Glyn Davies is also being investigated for lèse-majesté, Thai police say, after he gave a speech to foreign correspondents praising the monarchy but criticising the “lengthy and unprecedented prison sentences” handed down by Thai military courts.

The police have made clear he has diplomatic immunity.