From gigantic billboards on high-rises to portraits that flank leafy boulevards, images of King Bhumibol Adulyadej dominate the streets of Bangkok. Such is the cult of personality surrounding the world's longest-reigning monarch that some analysts have made comparisons with North Korea's fervour for its supreme commander.

Thailand King Bhumibol Adulyadej
A man cycles past a picture of Thailand's King Bhumibol Adulyadej in BangkokJorge Silva/Reuters
Thailand King Bhumibol Adulyadej
A garlanded picture of Thailand's King Bhumibol Adulyadej stands at the entrance to a low income neighbourhood in BangkokJorge Silva/Reuters
Thailand King Bhumibol Adulyadej
Placed in a low income area of Bangkok, children play next to an image of King Bhumibol Adulyadej, in celebration of the king's 88th birthday, in December 2015Jorge Silva/Reuters

After seven decades on the throne, King Bhumibol is accorded semi-divine status. Celebrations will include a morning religious ceremony presided over by 770 (seen as an auspicious figure) Buddhist monks. However, the kingdom marks his platinum jubilee amid anxiety over his health. The king received heart treatment this week and has been in hospital for much of the past decade.

The king's health is a matter of intense national concern due to unease about political stability during the succession. Most Thai people have known no other monarch. Crown Prince Vajiralongkorn, the king's 63-year-old son, is the heir apparent. He has not achieved the same level of devotion that his father enjoys.

Crowds gather whenever the king's convoy travels, and many people sport the colours of royal family members on their birthdays. The national anthem is played in public places every morning and evening and people are expected to stand at attention. Old footage of the king's visits to rural communities is shown when his anthem is played in cinemas before every film. Many national holidays revolve around the royals. The king's birthday is Father's Day and Queen Sirikit's is Mother's Day.

Thailand King Bhumibol Adulyadej
A picture of Thailand's King Bhumibol Adulyadej playing the saxophone hangs from a building in the financial district of BangkokJorge Silva/Reuters
Thailand King Bhumibol Adulyadej
A portrait of Thailand's King Bhumibol Adulyadej is seen on a road in BangkokJorge Silva/Reuters
Thailand King Bhumibol Adulyadej
Portraits of Thailand's King Bhumibol Adulyadej hang on a wall at a mechanical workshop in BangkokJorge Silva/Reuters
Thailand King Bhumibol Adulyadej
A woman works on a sewing machine on a street in Bangkok in front of a wall decorated with photographs of Thailand's King Bhumibol AdulyadejJorge Silva/Reuters
Thailand King Bhumibol Adulyadej
People walk past a picture of Thailand's King Bhumibol Adulyadej at a shopping mall in BangkokJorge Silva/Reuters
Thailand King Bhumibol Adulyadej
5 December 2015: A woman cries as she looks up at the hospital room of the ailing King Bhumibol Adulyadej at Siriraj hospital in Bangkok, on his 88th birthdayPaula Bronstein/Getty Images

For some, the reverence reflects conformity in a country known for adherence to age old customs and its love of uniforms. Others point to stringent royal insult laws (lèse majesté) which prevent criticism of the king – enforced with record jail terms under the junta that seized power in 2014.

The king's jubilee comes amid a crackdown on dissent ahead of August's referendum on a constitution that critics say would extend the military's influence at the expense of populist political forces emerging to challenge the establishment. If voters reject the draft charter, a general election slated for 2017 could be delayed, prolonging tension between the military-dominated establishment and its rivals seeking a quick return to electoral politics.

Educational reforms under the junta have emphasised loyalty and love of the monarchy. King Bhumibol's image is at the centre of every classroom in schools, where education is largely by rote learning.

Thailand King Bhumibol Adulyadej
Well-wishers hold a picture of Thailand's King Bhumibol Adulyadej outside Bangkok's Siriraj hospitalAthit Perawongmetha/Reuters
Thailand King Bhumibol Adulyadej
A well-wisher holds a new 70 baht banknote – printed to commemorate Thailand's King Bhumibol Adulyadej's 70th anniversary – at the Siriraj hospital in Bangkok, where the king is residingAthit Perawongmetha/Reuters
Thailand King Bhumibol Adulyadej
A well-wisher holds a picture of Thai King Bhumibol Adulyadej at the Siriraj hospital in Bangkok, where he is residingAthit Perawongmetha/Reuters
Thailand King Bhumibol Adulyadej
A man pushes a cart loaded with fruits past a painting of Thailand's King Bhumibol Adulyadej in BangkokJorge Silva/Reuters
Thailand King Bhumibol Adulyadej
Pictures of Thailand's King Bhumibol Adulyadej and Queen Sirikit hang on the wall in a store in BangkokJorge Silva/Reuters
Thailand King Bhumibol Adulyadej
A hostess sits at a restaurant in Bangkok, with paintings depicting Thailand's King Bhumibol Adulyadej hanging on the wallJorge Silva/Reuters
Thailand King Bhumibol Adulyadej
A man poses for a photograph to show his tattoo of Thailand's King Bhumibol Adulyadej in PhuketSooppharoek Teepapan/Reuters
Thailand King Bhumibol Adulyadej
Pictures of Thailand's King Bhumibol Adulyadej and Queen Sirikit hang at a store in BangkokJorge Silva/Reuters
Thailand King Bhumibol Adulyadej
A woman getting a haircut sits in front of a picture of Thailand's King Bhumibol Adulyadej having a haircut at a beauty salon in BangkokJorge Silva/Reuters
Thailand King Bhumibol Adulyadej
A picture of Thailand's King Bhumibol Adulyadej hangs on the wall of a food stall at a market in BangkokJorge Silva/Reuters
Thailand King Bhumibol Adulyadej
A woman working at a jewellery shop in Bangkok holds an amulet depicting Thailand's King Bhumibol AdulyadejJorge Silva/Reuters
Thailand King Bhumibol Adulyadej
A woman selling chicken sits in front of pictures of Thailand's King Bhumibol Adulyadej at a market in BangkokJorge Silva/Reuters
Thailand King Bhumibol Adulyadej
Pictures of Thailand's King Bhumibol Adulyadej hang on a wall of a street food stall in BangkokJorge Silva/Reuters
Thailand King Bhumibol Adulyadej
A firefighter sits in his Bangkok office, decorated with pictures of Thailand's King Bhumibol Adulyadej and Queen SirikitJorge Silva/Reuters
Thailand King Bhumibol Adulyadej
Officials walk out of a public building in Bangkok decorated with a picture of Thailand's King Bhumibol AdulyadejJorge Silva/Reuters
Thailand King Bhumibol Adulyadej
A player from the Thai national team displays a picture of King Bhumibol Adulyadej after winning the King's Cup at Rajamangala stadium in BangkokAthit Perawongmetha/Reuters
Thailand King Bhumibol Adulyadej
Bangkok's Suvarnabhumi Airport is decorated with pictures of Thailand's King Bhumibol AdulyadejJorge Silva/Reuters
Thailand King Bhumibol Adulyadej
A banner depicting Thailand's King Bhumibol Adulyadej and Queen Sirikit hangs on a government building in BangkokAthit Perawongmetha/Reuters
Thailand King Bhumibol Adulyadej
People eat on a street in Bangkok opposite a building with a picture of Thailand's King Bhumibol AdulyadejJorge Silva/Reuters
Thailand King Bhumibol Adulyadej
Students from Chulalongkorn University display a mosaic with a picture of Thailand's King Bhumibol Adulyadej during a football match in Bangkok on 13 February 2016Jorge Silva/Reuters

The monarchy has not always been held so highly in Thailand. In 1946, at the age of 18, King Bhumibol inherited a throne that had barely survived the upheaval of the end of absolute monarchy in 1932. That marked what an official biography of the king described as a nadir for the monarchy. Over the following decades, the king earned the adoration of millions through work in public health and rural development, and with the help of a formidable public relations machine that returned the monarchy to prominence in a country where politics, was, and still is, largely dominated by the military.

The military has staged 19 coups or attempted coups since the end of absolute monarchy, often evoking its loyalty to the crown and defence of the monarchy in explaining its actions.