The government has placed a temporary export ban on two relics from the Antarctic expeditions of Captain Scott and Sir Ernest Shackleton, following their sale to non-UK residents last year.

Arts minister Alan Howarth said a sledging flag from Scott's doomed trip to the South Pole in 1910 and a royal standard from Shackleton's Imperial Trans-Antarctic Expedition in 1914 were nationally important emblems of the "great heroic age" of Polar exploration.

However they were both bought by a private museum in Texas when the items were put on auction at Christie's last September. Scott's flag fetched �35,000 and the Shackleton standard sold for �64,000.

Mr Howarth gave museums and public donors until 19 April in order to raise around �100,000 to save the memorabilia.

The sale last year caused protest among many historians and some of the explorers' descendants. London's National Maritime Museum stepped in at the last minute to buy two other items - Scott's personal sledging flag and a compass belonging to Shackleton.

At a news conference at Christies in central London, Mr Howarth said: "They are emblematic of that great heroic age of polar exploration about 100 years ago and they are part of our national story - the patriotism, the gallantry, the heroism."

David Spence, exhibitions director at the National Maritime Museum, added: "These are not just unique items but are really inextricably bound with our country's notion of heroism."

He said his museum hoped to be able to display the flags alongside other polar artefacts to go on show at an exhibition in September to be called The Race to the Pole.

Other items which were sold last year included Scott's pipes, parts of the primus stove Scott and his companions used to cook their last meal before their fuel ran out, and even an uneaten biscuit.

Other poignant relics include empty summit ration bags valued at between �5,000 and �10,000, and a metal matchbox thought to be worth �600.

Scott's team succeeded in their goal of reaching the South Pole on 18 January, 1912, only to find the glory of being the first had already been taken by Norwegian explorer Roald Amundsen a month before.

The explorer and his party fought ferocious weather to return to their supply depot but died in their tent just a few miles from fresh supplies on, or shortly after, 29 March, 1912.

Their bodies were later recovered, together with Scott's diaries, and many of the items which are now up for sale.

Sir Ernest Shackleton abandoned an attempt to reach the Pole after becoming icebound during the winter of 1915-16.