Hong Kong (CNN) The crime of lese majeste -- insulting the royal family -- is a law enforced by monarchies around the globe. But few are stricter than Thailand.

Thailand stipulates harsh punishments for defaming or insulting the king or senior royals, and critics say it has stifled much needed debate over the country's future.

Even someone in whose name it's invoked in has questioned it. King Bhumibol Adulyadej said in 2005 that "if the King can do no wrong, it is akin to looking down upon him, because the King is not being treated as a human being."

But that hasn't stopped there being a huge spike in prosecutions in the last decade, with more than 400 cases in 2010 alone , according to Human Rights Watch.

Where does the law come from?

Photos: Thai King Bhumibol Adulyadej dies at 88 Photos: Thai King Bhumibol Adulyadej dies at 88 A Thai cyclist prays in front of the Grand Palace in Bangkok on October 16, 2016. Thousands of Thai men and women gather daily in the vicinity of the palace to pray for the late Thai King Bhumibol Adulyadej after his death Thursday. Hide Caption 1 of 18 Photos: Thai King Bhumibol Adulyadej dies at 88 A Buddhist monk stands next to line of mourners waiting to pay their respects to the body of the late King Bhumibol Adulyadej at the Grand Palace in Bangkok, October 15, 2016. Hide Caption 2 of 18 Photos: Thai King Bhumibol Adulyadej dies at 88 Devotees light candles for the late Thai King at Mahabodhi temple in Bodhgaya on October 14. Hide Caption 3 of 18 Photos: Thai King Bhumibol Adulyadej dies at 88 A Thai man carries high an image of Thailand's King Bhumibol Adulyadej as a large crowd floods the streets leading to the Royal Palace on October 14, 2016. Hide Caption 4 of 18 Photos: Thai King Bhumibol Adulyadej dies at 88 A van carries the body of Thai King Bhumibol Adulyadej's to his palace in Bangkok on October 14. Hide Caption 5 of 18 Photos: Thai King Bhumibol Adulyadej dies at 88 Thais gathering outside of Siriraj Hospital in Bangkok hold up baht notes with a portrait of Thailand's King Bhumibol Adulyadej on Friday, October 14, in Bangkok, Thailand, following news of his death the previous day. Hide Caption 6 of 18 Photos: Thai King Bhumibol Adulyadej dies at 88 A flag flies at half-staff outside a government hospital on October 14 in Chiang Mai, Thailand. According to a palace statement, all government buildings will fly the Thai flag at half-staff for 30 days starting on Friday. Hide Caption 7 of 18 Photos: Thai King Bhumibol Adulyadej dies at 88 Thai Prime Minister General Prayuth Chan-o-cha attends a traditional funeral bathing ceremony for the King at the Grand Palace in Bangkok on Friday. Hide Caption 8 of 18 Photos: Thai King Bhumibol Adulyadej dies at 88 The Prime Minister arrives to pay respects to the late King at the Grand Palace on October 14. Hide Caption 9 of 18 Photos: Thai King Bhumibol Adulyadej dies at 88 Dignitaries participate in a ceremony commemorating the King at Wat Phra Singh on Friday in Chiang Mai. Hide Caption 10 of 18 Photos: Thai King Bhumibol Adulyadej dies at 88 Buddhist monks line up to offer condolences at the Grand Palace in Bangkok on Friday. Hide Caption 11 of 18 Photos: Thai King Bhumibol Adulyadej dies at 88 People dressed mostly in black wait outside the Grand Palace to pay respects to the King on October 14. Hide Caption 12 of 18 Photos: Thai King Bhumibol Adulyadej dies at 88 The Thai Royal Guard marches in honor of Thai King Bhumibol Adulyadej on Friday. Hide Caption 13 of 18 Photos: Thai King Bhumibol Adulyadej dies at 88 Amid a procession of vehicles, a van carries the body of the King to his palace in Bangkok on Friday. Hide Caption 14 of 18 Photos: Thai King Bhumibol Adulyadej dies at 88 Mourners shade themselves under umbrellas while they await the procession of the King's body to the palace in Bangkok on October 14. Hide Caption 15 of 18 Photos: Thai King Bhumibol Adulyadej dies at 88 A woman passes out after an official statement announces the death of the king. Hide Caption 16 of 18 Photos: Thai King Bhumibol Adulyadej dies at 88 People react to news of the King's death outside Siriraj Hospital in Bangkok on Thursday. Hide Caption 17 of 18 Photos: Thai King Bhumibol Adulyadej dies at 88 A women cries after learning of the King's death on October 13 in Bangkok. Hide Caption 18 of 18

Lese majeste (lez majest-ay) comes from the Latin laesa maiestas, or "injured majesty." Though it has become increasingly associated with Thailand in recent years, the crime dates back to the Roman Republic, and was massively expanded during the reign of Emperor Tiberius (14-37 AD), according to historian Theodor Mommsen

Countries as diverse as the Netherlands Norway and Jordan all still have laws against lese majeste.

The law was added to Thailand's Criminal Code in 1908, and was expanded after a military coup in 1976 to make it illegal to defame, insult or threaten the king, queen, heir-apparent or regent, said David Streckfuss, author of " Truth on Trial in Thailand ."

"The number of cases started going up in 2005," Streckfuss said, before "skyrocketing" in the early 2010s.

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What are the punishments?

Those found guilty of lese majeste can be jailed for between three and 15 years for each count, with some sentences stretching to 60 years

Since 2007, extra protections have been enshrined in the constitution, with Article 8 staying that "the King shall be enthroned in a position of revered worship and shall not be violated. No person shall expose the King to any sort of accusation or action."

Prime Minister Prayuth Chan-ocha has defended lese majeste as required to protect the monarchy, saying in 2014 that "his majesty is not in a position to respond or explain."

The law "is not aimed at curbing people's rights to freedom of expression nor the legitimate exercise of academic freedom, including debates about the monarchy as an institution," Thai foreign ministry official Sek Wannamethee wrote earlier this year.

How has the law been used?

Photos: Thailand's King Bhumibol Adulyadej: A life in pictures Photos: Thailand's King Bhumibol Adulyadej: A life in pictures Thailand's Bhumibol Adulyadej was crowned king on May 5, 1950. News of the 88-year-old's death was announced Thursday, October 13, via a statement from the Royal Palace read on state TV. He was the world's longest-reigning living monarch. Hide Caption 1 of 16 Photos: Thailand's King Bhumibol Adulyadej: A life in pictures Bhumibol, left, is pictured in 1935 with his older brother, the former King Ananda Mahidol, in Lausanne, Switzerland, where the boys attended school. King Ananda was 20 when he died of a gunshot wound under mysterious circumstances. His 18-year-old brother, known then as Prince Phumiphon Aduldet, later assumed the throne to become King Bhumibol Adulyadej. Hide Caption 2 of 16 Photos: Thailand's King Bhumibol Adulyadej: A life in pictures Bhumibol and his future wife, Princess Sirikit Kityakara, are pictured in Lausanne in 1949. The couple married a year later at Srapathum Palace in Bangkok, Thailand. Hide Caption 3 of 16 Photos: Thailand's King Bhumibol Adulyadej: A life in pictures The King and Queen pose with their children, Crown Prince Vajiralongkorn and Princess Ubol Ratana, on the steps of Bangkok's Chitralada Palace in 1955. Two more daughters, Princesses Maha Chakri Sirindhorn and Chulabhorn Walailak, were born in 1955 and 1957. Hide Caption 4 of 16 Photos: Thailand's King Bhumibol Adulyadej: A life in pictures The royal couple ride with U.S. President Dwight Eisenhower during a five-day state visit to the United States in 1960. Hide Caption 5 of 16 Photos: Thailand's King Bhumibol Adulyadej: A life in pictures The King, far right, plays the saxophone during a 1960 jam session with legendary jazz clarinetist Benny Goodman and his band in New York. Hide Caption 6 of 16 Photos: Thailand's King Bhumibol Adulyadej: A life in pictures The King walks with his wife and their 13-year-old son, Crown Prince Vajiralongkorn, during a visit to Britain in 1966. Hide Caption 7 of 16 Photos: Thailand's King Bhumibol Adulyadej: A life in pictures The King convenes the first meeting of his country's National Reform Assembly during a ceremony held in Bangkok in 1976. The King put the monarchy at the center of Thai society, acting as a force for community and tradition even as the country flipped between political crises and military coups. Hide Caption 8 of 16 Photos: Thailand's King Bhumibol Adulyadej: A life in pictures The King raises a camera to take a photo in 1995. He was given his first camera in 1934, which ignited a lifelong enthusiasm for photography. He has often been seen with a camera around his neck during public appearances. Hide Caption 9 of 16 Photos: Thailand's King Bhumibol Adulyadej: A life in pictures The King and Queen survey a rice crop made possible by a Royal Irrigation Project in 1996. The project formed part of the Royal Development Projects, which focused on developing remote rural areas. The King has taken an interest in environmental projects throughout his long reign. Hide Caption 10 of 16 Photos: Thailand's King Bhumibol Adulyadej: A life in pictures The King reviews an honor guard with Queen Sirikit and Crown Prince Vajiralongkorn during the annual military parade to celebrate his birthday in 2006. Hide Caption 11 of 16 Photos: Thailand's King Bhumibol Adulyadej: A life in pictures The King lights candles at a ceremony to mark Coronation Day in Bangkok in 2007. Hide Caption 12 of 16 Photos: Thailand's King Bhumibol Adulyadej: A life in pictures The King is wheeled towards his yacht in 2010, during a rare public appearance to open a new flood gate and two bridges in Bangkok. Hide Caption 13 of 16 Photos: Thailand's King Bhumibol Adulyadej: A life in pictures The King is pictured with family members in 2012. He addressed a crowd from a balcony on his 85th birthday. Hide Caption 14 of 16 Photos: Thailand's King Bhumibol Adulyadej: A life in pictures The King is seen through a car window as he leaves the Siriraj hospital in Bangkok in 2015. Hide Caption 15 of 16 Photos: Thailand's King Bhumibol Adulyadej: A life in pictures A portrait of the King is held on the eve of his 88th birthday as people gather outside the Siriraj hospital in 2015. The King of Thailand is regarded as a demi-god by many Thais, and his popularity has been viewed as a unifying force during times of political unrest. Hide Caption 16 of 16

Despite its long pedigree, there is no clear legal definition of what exactly constitutes lese majeste, and complaints can be filed by anyone, from officials to members of the public.

Police are obliged to investigate cases, not doing so could potentially put them in breach of lese majeste themselves, according to Streckfuss.

"The strength of lese majeste is that it's unclear where its lines are. That's its power," he said.

Last year, police opened an investigation into US Ambassador Glyn Davies over claims he may have breached lese majeste during a speech at the Foreign Correspondents Club Thailand. Davies, who has diplomatic immunity under international law , was not charged.

In one of the most highly-publicized instances in recent years, 27-year-old Thanakorn Siripaiboon was charged with "liking" a Facebook page deemed insulting to the king and posting a sarcastic photo of Bhumibol's beloved pet dog. Thanakorn's lawyer told CNN his client had been indicted and was still awaiting trial. He faces up to 37 years in prison

Nor is intention to offend necessarily required. In 2012, Ekachai Hongkangwan, 37, was sentenced to three years in prison for selling copies of an Australian documentary about the royal family. The accuracy of the claims in the film had no bearing on the case, the judge said at the time , "because if it is true, it is more defamatory and if it isn't true, then it's super defamatory."

What effect does it have?

The broad scope of the law can make it next to impossible to discuss or speculate on certain issues surrounding the royal family or the succession, said Streckfuss.

"In the name of protecting the monarchy, the junta is tightening a chokehold on free expression and heightening a climate of fear across Thailand" via lese majeste prosecutions, Human Rights Watch said in May

Media organizations, especially those based in Thailand, are limited on what they can report on the royal family, with reporters, editors and publishers liable to be charged should an article fall foul of the law.

Even articles discussing lese majeste cases themselves are risky, as reporting what the accused said or did can be an offense in itself.

"There are incidents where the reporter has been charged for quoting someone else and the person who said it was not charged," said Streckfuss.