Explorer Henry Worsley, who was on the brink of making Antarctic history with a solo crossing across the ice, has died, his family has announced.
The former Army officer was 71 days into his attempt to become the first adventurer to cross the continent completely unsupported and unassisted when he had to call for help and was airlifted off the ice on Friday.
His wife Joanna said in a statement: "It is with heartbroken sadness I let you know that my husband, Henry Worsley, has died following complete organ failure; despite all efforts of ALE and medical staff at the Clinica Magallanes in Punta Arenas, Chile."
Battling temperatures of minus 44, tackling white-out blizzards and treacherous ice, the ex-lieutenant colonel, who was 55, had passed the South Pole.
He had covered 913 miles and was only 30 miles from the end of the challenge.
After spending two days unable to move from his tent, the married father-of-two took the decision to pull out of the charity adventure after suffering from exhaustion and severe dehydration.
He was flown to a hospital in Punta Arenas where he was found to have bacterial peritonitis. He underwent surgery but died on Sunday in hospital.
Worsley, of Fulham, London, was attempting to complete Sir Ernest Shackleton's unfinished journey to the South Pole.
He was trying to recreate the majority of the untravelled journey 100 years after Shackleton's hopes of becoming the first team to cross the Antarctic continent were crushed.
Shackleton's ship Endurance was trapped and sunk by pack ice in 1915, leaving his team stranded.
His wife Joanna also paid tribute to her husband for reaching his goal of raising more than £100,000 to help wounded servicemen and women.
The trek was raising money for the Endeavour Fund, a charity managed by the Royal Foundation of The Duke and Duchess of Cambridge and Prince Harry.
"Henry achieved his Shackleton Solo goals: of raising over £100,000 for the Endeavour Fund, to help his wounded colleagues, and so nearly completing the first unsupported crossing of the Antarctic landmass," she said.
"A crossing made, under exceptionally difficult weather conditions, to mark the 100th anniversary of Sir Ernest Shackleton's Endurance expedition - his lifelong hero.
"On behalf of myself and family, I wish to thank the many hundreds of you who have shown unfailing support to Henry throughout his courageous final challenge and great generosity to the Endeavour Fund.
The donation total is currently at more than £106,773.
The Duke of Cambridge expressed his immense sadness at the explorer's death, saying he and Prince Harry had lost a friend.
He paid tribute to Henry Worsley's "selfless commitment" to his fellow servicemen and women, and pledged to make sure his family receive all they support they need.
"Harry and I are very sad to hear of the loss of Henry Worsley. He was a man who showed great courage and determination and we are incredibly proud to be associated with him," William said.
"Even after retiring from the Army, Henry continued to show selfless commitment to his fellow servicemen and women, by undertaking this extraordinary Shackleton solo expedition on their behalf.
"We have lost a friend, but he will remain a source of inspiration to us all, especially those who will benefit from his support to the Endeavour Fund.
"We will now make sure that his family receive the support they need at this terribly difficult time."
In his final statement sent from Antarctica, Lt Col Worsley described how his desire to help wounded soldiers with their rehabilitation was the central focus of his expedition.
He said: "Having been a career soldier for 36 years and recently retired, it has been a way of giving back to those far less fortunate than me.
"The 71 days alone on the Antarctic with over 900 statute miles covered and a gradual grinding down of my physical endurance finally took its toll today, and it is with sadness that I report it is journey's end - so close to my goal."