Image copyright Christie's Image caption Medals awarded to Sir Ernest Shackleton are to be sold at auction

Medals awarded to adventurer Sir Ernest Shackleton for his expeditions to the Antarctic are to be sold at auction.

They include the polar explorer's Royal Geographical Society's Silver Medal - which he received for his role in the 1901 Discovery expedition.

The medal - which is one of 14 separate lots - is expected to sell for between £20,000 and £40,000, Christie's said.

A medal recognising the rescue and survival of the crew of the 1914 Endurance expedition will also be sold.

Last year marked the 100th anniversary of the start of the ill-fated expedition led by Shackleton, which hoped to make the first land crossing of the Antarctic.

After sailing to the Atlantic, the team's boat - called Endurance - became trapped in the Antarctic ice and sank 10 months later.

Royal Victorian Order

Shackleton's crew abandoned the ship to live on the floating ice and in April 1916 set off in three small boats, eventually reaching Elephant Island.

Taking five crew members, Shackleton then went to find help and the six men spent 16 days crossing 1,300km (810 miles) of ocean to reach South Georgia.

They trekked across the mountainous island to a whaling station to get help.

The remaining men were rescued in August 1916. There were no fatalities.

Shackleton was later awarded the Chilean Order of Merit, recognising the rescue and survival of the crew, which is to be sold during the auction and is expected to reach between £4,000 and £6,000.

The medal Shackleton received when made Commander of the Royal Victorian Order for reaching the farthest South ever explored is estimated to sell for £20,000 to £30,000.

The sale will be held in London on 8 October.

Image copyright Christie's Image caption The Royal Geographic Society's Silver Medal, awarded after the landmark Discovery expedition

Image copyright Christie's Image caption Sir Ernest Shackleton's Chilean Order of Merit

Image copyright PA Image caption The explorer led three British expeditions to the Antarctic