A copy of the Magna Carta - the document which effectively gave birth to democracy in the UK - should not be exported overseas, the Culture Secretary said.

The manuscript dating from 1300 was given to Faversham, Kent, and is among seven surviving editions from that year.

The Sunday Times reported the town council is considering selling the artefact which could be worth more than £20 million but Nicky Morgan told the paper it should not "leave these shores".

King John, who is buried in Worcester Cathedral, issued the Magna Carta after agreeing peace terms with a band of rebel barons and it is now one of the world's most celebrated legal documents.

It established for the first time that neither monarch nor government was above the law and set out principles of liberty which echoed through the centuries.

Four original charters dating from 1215 are held at the British Library, Lincoln and Salisbury cathedrals, while the Faversham impression was presented to the barons of the town in the early 14th Century.

Mrs Morgan, who is not standing in this month's General Election, told the newspaper: "I'm extremely concerned to hear about the possible sale of Magna Carta by Faversham council.

"It is one of the most important documents in British history. I, and any future Conservative minister, will do everything we can to block this precious artefact from leaving these shores."

King John died of dysentery contracted whilst on campaign in eastern England during late 1216;