It is most fitting that these relics of the heroic age of Antarctic exploration have been saved for the nation

Nicholas Lambourn, Christie's

The papers covered the epic adventures of Antarctic legend Sir Ernest Shackleton. They were deemed so important that the UK's National Heritage Memorial fund released substantial sums to ensure the documents did not go to foreign bidders.

The papers - a diary and archive - were compiled by Shackleton's doctor and fetched more than £200,000. They will now go into the safe keeping of the Scott Polar Research Institute in Cambridge.

Macklin's diary of events will be held at the Scott Polar Research Institute

Nicholas Lambourn, the Christie's specialist in charge of the sale, said: "It is most fitting that these relics of the heroic age of Antarctic exploration have been saved for the nation."

Other highlights at the sale included a 100-year-old Cadbury's chocolate bar, which went on Captain Robert Scott's Discovery expedition (1901-1904), his first to the White Continent.

The 10-centimetre-long bar, wrapped uneaten in a cigarette tin, was snapped up for £470, including the buyer's premium, by an unnamed chocoholic.

Huge draw

The Polar Sale included more than 200 items relating to Arctic and Antarctic exploration - the highlight being the Shackleton Collection, which detailed the explorer's life from his early journey on Scott's Discovery expedition until his death at South Georgia in 1922.

The Cadbury's bar of chocolate went to an unnamed individual

There were portraits, photographs, letters, and books up for auction - but the lots of greatest historical value were the ones that included papers belonging to Alexander Macklin, a doctor on Shackleton's now legendary Endurance adventure of 1914-1917.

This was the expedition to Antarctica during which Shackleton's ship became trapped in ice in the Weddell Sea. The crew was marooned for months before managing to escape to Elephant Island in three small boats.

Macklin's diary contains one of the few records of what happened on the island after Shackleton left his men to summon help. The journal was valued prior to auction at £50,000-£80,000 - but eventually sold for £104,950.

William Mills, keeper and librarian of the Scott Polar Research Institute, described the journal's acquisition as "fantastic news".

Macklin's papers describe Shackleton's death

"It's one of the very few, key sources of information from that period," he told BBC News Online. "The institute's got a couple of other diaries from Elephant Island, but it's wonderful that we now have Macklin's."

The doctor's documentation from Shackleton's final expedition, the Shackleton-Rowett Antarctic Expedition, was also up for sale. These papers were valued at £60,000-£80,000, but fetched £100,550.

"This was probably the last opportunity to secure the archive in its entirety," Mr Mills said. "It includes individual items such as Shackleton's death certificate and Macklin's description of the explorer's death.

"This expedition also marked the end of the heroic era and the start of something new; it was the first to try to mount an essentially oceanographic expedition to Antarctica that would involve full use of aircraft."

The institute will catalogue the new acquisitions and then put them on public display. If sufficient funds can be raised, an online exhibition will also be posted.