Two climbers attempting to recreate British mountaineer George Mallory's pioneering climb of Mount Everest using only 1920s gear had to change to modern clothes because of the cold, a spokeswoman said on Thursday.

Conrad Anker, an American climber who in 1999 discovered Mallory's frozen body about 2,030 feet below the summit, wanted to see if it was possible for Mallory to have reached Mount Everest's summit in 1924.

Anker, 44, along with his 27-year-old British climbing partner Leo Houlding, set off to retrace Mallory's route this week.

But in the end they decided it was too cold to shun modern hi-tech textiles in favor of replicas of the clothes worn by Mallory and his climbing mate, Andrew Irvine, who also never returned from the mountain and whose body has never been found.

"They decided it would be unsafe," said Kate Fraser, a spokeswoman for Altitude Films, a London-based firm who filmed Anker's and Houlding's ascent.

However, they successfully free-climbed the Second Step after removing a ladder fixed to the treacherous 100-foot rock wall near the summit, and reached the peak of the world's highest mountain on Thursday, said Fraser.

"In this way the climbers confronted the Second Step very much as Mallory and Irvine might have done 83 years ago," Fraser said in an e-mail. "Their success at the summit, without the use of the ladder, adds weight to the theory that George Mallory and Sandy Irvine may have made it to the summit in 1924, 29 years before Hillary and Tenzing," she added.

In 1953, New Zealander Sir Edmund Hillary and Tenzing Norgay Sherpa became the first to successfully climb the mountain, almost 30 years after Mallory's pioneering attempt.

Notes: Qomolangma also known as Everest in west