A blood stained silk purse carried by Lord Nelson at the Battle of Trafalgar has been unveiled to the public.

It is part of a collection, including love letters from his wife and his mistress Lady Hamilton, which has been hidden away for 200 years.

The items belonged to descendants of Alexander Davison, Nelson's friend and banker.

These are not just historical items. This is history before us

Martyn Downer, Sotheby's

The treasures were "discovered" when the Davison family asked Sotheby's auction house to value one item - a diamond, anchor-shaped brooch initialled HN.

Sotheby's expert Martyn Downer said: "When I realised the significance of the items, and especially the purse that Nelson carried at Trafalgar, it was a heart-stopping moment.

"These are not just historical items. This is history before us."

The brooch is expected to fetch about �150,000 at auction

The purse still contained the 21 gold coins Nelson placed in it on the morning of his death.

Lady Nelson's heartbreak

However, he said the blood could be anyone's.

Mr Downer said: "By the time Nelson fell, the deck of his ship, the Victory, was awash with blood."

The purse is expected to go under the hammer for up to �80,000.

The collection also contains 72 letters from Lady Nelson to Mr Davison, detailing her heartbreak over her husband's affair with Lady Hamilton.

Coins were still inside the purse

Ceremonial swords and two wine coolers are also in the collection, described by Tom Pocock, Nelson's biographer, as "the most remarkable Nelsonian archive and collection to be discovered for more than a century".

The sword was made to commemorate Nelson's victory over the French at the Battle of the Nile in 1798.

The entire Davison collection will be sold on Trafalgar Day, on 21 October this year - almost 200 years since the battle and Nelson's heroic death in 1805.

The entire collection is estimated to be worth between �700,000 and �900,000.