A copy of the US Declaration of Independence has been discovered in Britain.

The document, which is in perfect condition, is believed to be one of only 200 printed and was stumbled upon among files at the National Archives in Kew, southwest London, by an American doing research.

Printed on July 4, 1776, it brings the total of known surviving copies worldwide to 26. The first official printings of the Declaration are known as Dunlaps: the name of the printer, John Dunlap, is given on each copy. This manuscript was hidden among correspondence from American colonists intercepted by the British in the 18th century.

In 2000 a Dunlap print that had been found at a flea market in 1989 fetched $8.14 million at auction.

The finding of the poster-size document brings the number of copies held at the National Archives to three, and despite its value, Mel Hide, a spokeswoman from the National Archives said that they would not be selling the print.

She said: “We will protect and preserve this copy. It is unlikely to go on display because we already have one on show at the Archives museum.”

But she did not rule out a trip across the Atlantic for the manuscript.

“The Americans are very excited by it. We do often loan out our key documents and I’m sure if an American institution wanted to borrow it, we would consider lending it to them,” Ms Hide said.

Edward Hampshire, the diplomatic and colonial specialist at the National Archives, said: “This is an incredibly exciting find. The Declaration of Independence is effectively America’s birth certificate.

“It is likely that only around 200 of these were ever printed, so uncovering a new one nearly 250 years later is extremely rare, especially one in such good condition.”

The Declaration of Independence, adopted by the Continental Congress, announced that the 13 American colonies then at war with Britain were independent states and no longer a part of the British Empire.

Prints made by Dunlap were delivered to the Founders early on the morning of July 5, 1776. One copy was officially entered into the Congressional Journal and the additional copies were distributed across the colonies to be read aloud.

Explore UK News

• Crime News

• Education News

• Health News

• Scotland News

Times Recommends

• Shrinking violet Gordon turns into raging bull
• Eddie Izzard: 'I keep thinking if I do all these things she'll come back'
• Is sex for the disabled the last taboo?