The only surviving Union Jack from the 1805 Battle of Trafalgar sold at auction for nearly 40-times its estimate, bringing an incredible £384,000.

The huge flag, flown from the jackstaff of the HMS Spartiate, is today ridden with bullet holes and has a distinct whiff of gunpowder.

Despite its damage from the battle which claimed 4,000 sailor's lives, the flag remains in excellent condition.

The 11ft flag has been kept by the descendents of Lieutenant James Clephan, hugely respected among his men, after being pressed into the Navy in 1794, aged 26, and rising through the ranks.

"Clephan is a remarkable and charismatic survivor from the great age of Georgian sale," said a spokesman for Charles Miller Auctions, according to the UK newspaper the Daily Mail.

Lieutenant Clephan would later rise to the rank of Captain over his own ship, "an incredible achievement for someone who had been pressed," said the spokesman.

The flag was presented to the Lieutenant after the British victory at the Battle of Trafalgar.

Union Jack from the 1805 Battle of Trafalgar (£384,000)

Clephan's descendants kept the flag in a darkened drawer over the years to ensure that it stayed preserved, eventually deciding to sell it upon emigrating to Australia.

It went under the hammer valued at just £10,000 - before going on to set what is believed to be the world record for a Union Jack at auction.

"We are hugely delighted and thrilled with the price, as are James Clephan's family," said a spokesman for Charles Miller Auctions.

"It is way above anyone's expectations, but does reflect the historical importance of the flag and the battle it fluttered in 204 years ago."

The flag was purchased by a US citizen but it is currently not known whether the flag will stay in Britain or go abroad.

The new owner is waiting for a British Museum to see if they will match his bid.

Photo: Charles Miller Auctions