A Nepalese former British army soldier has climbed all 14 of the world’s 8,000-metre-high mountains in a record-breaking 189 days – a feat that has taken other climbers years to achieve.

Nirmal “Nims” Purja, who came to international attention this year with the publication of his shocking photograph of a queue of climbers close to the summit of Everest, completed the last of his 14 climbs, to the summit of Shishapangma, at 8.58am local time on Tuesday, almost exactly on the schedule predicted by his support team last week.

‪“Mission achieved!” Purja reported from the summit with his teammates Mingma David Sherpa, Galjen Sherpa and Gesman Tamang.

Climbing all of the Himalayan giants has long been one of mountaineering’s most sought-after prizes, and was first achieved by Reinhold Messner in 1986, who was also was the first to climb all the 8,000ers without supplemental oxygen. In 2010, Edurne Pasaban became the first woman to complete all the 8,000ers.

Purja opted to use supplementary oxygen for his ascents, justifying his choice by the huge size of the challenge he had set himself.

“I have to get back down, so that I can reach the next mountain. I listen to my body. You must have humility so that you can get home. You can always go again without oxygen if that is what is so important, but you can’t if you’re dead.”

Facebook Twitter Pinterest Nirmal Purja’s photograph taken in May this year showing a queue of climbers waiting to reach Everest’s summit. Photograph: Nirmal Purja/AP

Purja was born in the Dhaulagiri region of Nepal, at an altitude of 1,600 metres, and grew up in Chitwan before joining the Gurkhas in 2003 and later the Special Boat Service.

His extraordinary series of ascents makes him one of the most successful climbers at the highest altitudes, joining only a handful of other mountaineers who have climbed all of the 8,000-metre peaks in the Himalayas. Notably he climbed Everest, Lhotse and Makalu (the fourth and fifth highest peaks in the world) consecutively in just 48 hours.

The previous record was held by Kim Chang-ho, of South Korea, who took seven years, 11 months and 14 days.

“I am overwhelmed and incredibly proud to have completed this final summit and achieved my goal of climbing the world’s 14 tallest mountains in record time,” said Purja after his final ascent.

Facebook Twitter Pinterest Mount Everest and Lhotse. Nirmal Purja completed both peaks and the nearby Makalu in 48 hours. Photograph: Alamy Stock Photo

The extraordinary achievement was quickly hailed by Alan Hinkes, the first Briton to climb all the 8,000-metre mountains, who took over 15 years to complete his round of ascents and who knows Purja.

“I remember celebrating at Shishapangma base camp, which was my first 8,000-metre mountain, with [the late Polish climber] Jerzy Kukuczka, who had just become the second person to climb all 14, thinking then that it was mind-blowing,” he told the Guardian.

“At that stage more people had stood on the moon than had climbed all 14. It seemed like an impossible thing to do. Later I recall thinking maybe it could be done in a single year with the right support. But not less than seven months.

“Even getting up Everest is a big challenge and it is very well set up. Doing the others is far more challenging. You have to be able to suffer to climb an 8,000er. It’s almost beyond description how difficult it is. Your head feels like it’s bursting and you are gasping for air.

“Nims is superbly fit, both physically and mentally – the right man at the right time. There is a little bit of luck. He had a good spell of weather in the [notoriously unsettled] Karakoram. But you make your own luck as well.”

Purja began the challenge, nicknamed Bremont Project Possible, when he reached the top of Annapurna on 23 April this year and has accomplished his feat with a rotating support team made up of exclusively Nepalese climbers.

On 22 May, he reached the summit of Mount Everest along with 320 other mountaineers. It was on this climb that he took the photo seen around the world of a “traffic jam” to reach the summit, bringing global attention to the mountain’s dangerous overcrowding.

The achievement is even more extraordinary as uncertainties in weather and conditions can reduce the window of opportunity for climbing even one mountain to a handful of days.

Purja and his team were also required to obtain a special climbing permit from the China Tibet Mountaineering Association to complete his challenge when China closed Shishapangma for other climbers this season.

Facebook Twitter Pinterest Annapurna, where Nirmal Purja and his team rescued a fellow climber during their descent. Photograph: Dutourdumonde/Alamy Stock Photo

The challenges of high-altitude mountaineering also leave the human body vulnerable to problems including the build-up of fluid on the brain and lungs as well as minor infections and other illnesses.

As well as his successful ascent this year, Purja was also involved in four rescues.

On 23 April, days into his world record attempt and descending Annapurna, Purja led a rescue of Dr Chin Wui Kin, who had been separated from an accompanying expedition and left without food, water or an oxygen bottle for 40 hours.

On 15 May, having made it to the summit of Kanchenjunga in 21 hours, Purja and his team rescued a further two climbers from a height of 8,400 metres and sacrificed their own supplementary oxygen to the climbers in need.