Scott on his later tragic expedition to the South Pole

Captain Albert Armitage poured his thoughts into a diary during the voyage of the Discovery to the Antarctic from 1901 to 1904.

In it he speaks of his enthusiasm early on for working with Scott but later he writes of rivalry between them.

The book is now to be auctioned and a campaign launched to keep it in the UK.

Rob Headland, of the Scott Polar Research Institute in Cambridge, is trying to raise the estimated �40,000 to keep the diary for future generations.

The book, still almost perfect inside, has been held privately for a century.

In such a case a diary tends to be almost a man's confessional Rob Headland, of the Scott Polar Research Institute

In the diary Captain Armitage says he was proud to be serving under Captain Scott on their journey, fraught with danger and discovery, to the unknown continent.

"It is very agreeable to be associated with Captain Scott who is at once both clear-headed, amiable and considerate," he wrote on 30 October 1902.

Later he recorded tense conversations with Scott in minute detail, revealing a bitter rivalry between the two Polar explorers.

"In such a case a diary tends to be almost a man's confessional," Mr Headland said.

"He's writing things as they occur at the time which, on reflection 24 hours or a week or so later, might be construed a little differently."

Scott at Mount Erebus (Image by Scott Polar Research Unit)

Rupert Powell, of Bloomsbury Auctions, said he was not surprised by the interest the diary was generating.

"There are not a huge amount of works written about the Antarctic - certainly not from the golden age back in the early 20th Century."

But the diarist has taken some of his secrets to his grave.

At one point he wrote: "When the captain went to turn in I went to the cabin to ask the reason for his unfriendly manner towards me. After hesitating for a little...." and there it ends.