They have stood for hundreds of years, but Britain's ancient trees are increasingly threatened by vandalism, disease and development.

Now a list of 20,000 of the oldest, most precious trees has been compiled in an attempt to protect them.

From a 5,000-year-old yew said to have sheltered the young Pontius Pilate, to an oak which inspired Mendelssohn and a sycamore under which the Tolpuddle Martyrs met, many of the trees have played a key role in the nation's history.

Britain has more old trees than anywhere else in northern Europe, but many are now at risk. Although some can be protected by preservation orders, conservationists say these can be rescinded if a tree is claimed to be dead, dying or dangerous. The Government is preparing to bring in rules that would give greater protection to ancient trees and conservationists have compiled the register to highlight as many as possible.

Jill Butler, from the Woodland Trust, which compiled the list with the Ancient Tree Forum and the Tree Register of the British Isles, said: "These are representatives of our history and heritage, in the same way that old buildings are."

Trees are classified according to three stages - growing, mature or ancient.

Once a member of the public has nominated what he or she believes to be an ancient tree, a verifier from the register will study its girth and the conditions in which it is growing. From this age can be established and whether it qualifies as ancient.

10 prominent trees from the woodland trust

Fortingall Yew, Perthshire

Up to 5,000 years old and believed to be the oldest living organism in Europe. According to local legend, Pontius Pilate, the Roman governor of Judea who oversaw the crucifixion of Jesus, was born in the shade of this tree and played beneath it as a child.

Haresfield Oak, Gloucestershire

With a girth of more than 23ft, this tree was reputedly planted to mark the route that the funeral cortège for Edward II took from Berkeley Castle to Gloucester in 1327.

Druid's Oak, near Farnham Common, Buckinghamshire

Has a girth of nearly 30ft and is thought to be up to 1,000 years old. Felix Mendelssohn is said to have composed some of the music for A Midsummer Night's Dream while visiting these woods.

Wesley's Elm, Stony Stratford, Milton Keynes

John Wesley visited Stony Stratford five times and is said to have stood beneath this tree to deliver his sermons. Up to 300 years old, with a girth of more than 25ft, it has been damaged by vandals and reduced to little more than a hollow.

Dickens Oak, Chigwell

At least 300 years old, with a girth of almost 20ft, the tree is near to The King's Head pub which Charles Dickens portrayed as The Maypole in Barnaby Rudge. On a verge between a busy road and a footpath, it is in good health, despite suffering damage.

Law Day Oak, Bonnington, Kent

Has been used as a venue for the administration of justice since at least the reign of Elizabeth I. An annual parish meeting is still held beneath its branches.

Treflach Hall Cedar, Shropshire

One of the youngest trees on the register, as the species was not introduced until the 1630s. The tree has survived well, despite losing a branch when hit by a low-lying RAF Hercules during a night exercise.

Oriental plane tree, Wokingham

In the grounds of a supermarket and believed to be about 800 years old. Mysteriously absent from a 1739 engraving of the area.

Queen Elizabeth Oak, Northiam, East Sussex

On August 11, 1573, Elizabeth I stopped in the village on her way to Rye, sat beneath the 1,000-year-old tree and ate a meal served to her from the house nearby. She changed her shoes of green damask silk and left them as a memento. In 1944, the area around the tree was used to inspect troops ahead of D-Day.

The Martyrs' Tree, Tolpuddle, Dorset

A sycamore pollard, which began life 150 years before a group of disgruntled labourers met beneath it in 1834 and formed an organisation that was the precursor of modern trade unions. The members of the group were later transported to Australia