Historians searching for the true location of one of the Battle of Bosworth say new findings have changed their understanding of medieval warfare.

Experts who undertook a four year investigation to pinpoint the site of the Battle of Bosworth announced yesterday they had uncovered the first hard evidence of cannon and gunpowder used in a major conflict anywhere in the world.

More than 20 pieces of lead roundshotwere discovered on land between Upton , Shenton, Dadlingtonand Stoke Golding

The find has led historians to believe the battle between the then King of England Richard III and Henry Tudor on August 22, 1485, took place in this location and not Ambion Hill, near Sutton Cheney which was always thought to be the battle site.

Archaeologists have refused to be more precise about the location for fear of illegal treasure seekers.

Battlefields Trust archaeologist Glen Foard said: "The archaeological survey has so far produced 22 lead roundshot fired from artillery and bullets from early hand guns - more than all the lead roundshot from all the other battlefields of the 15th and 16th century in Europe put together.

"Bosworth has shown the potential of archaeology to contribute to our understanding of the origins of firepower - a story of international significance which now must be explored on battlefields across Europe."

The discoveries are set to go on show to the public from Easter next year. In the meantime experts will continue their search to define the extent of the battlefield.

Despite the discovery, there are no plans to move a stone memorial on the spot where Richard III was previously been thought to have been slain at Ambion Hill.

Bosworth's Heritage Centre itself, which has attracted more than 500,000 since it opened in 1974, will also remain in place.

For over 200 years the battle was thought to have been fought on Ambion Hill, a theory based on old maps.

However a "vociferous" debate began in 1985 over the true location of the battle, with at least four contending sites being put forward.

Among alternative sites suggested was the one to the west of Dadlington as suggested by Dr Peter Foss.

His theory was based on discovering marsh land which was alluded to in the 16th century writings of Virgil. However subsequent studies have found the marsh would have disappeared many centuries before the battle.

Mr Foss said: "These new discoveries contribute enormously to our current knowledge, and are a tribute to the commitment of the team."

During the survey experts also confirmed "almost certainly" that Crown Hill near Stoke Golding was the site where Henry Tudor was crowned Henry VII King of England after his victory .

Helen Emery, project director of Bosworth Battlefield, added: "The news today is truly amazing and very exciting. All the Heritage Centre team have supported and encouraged the research throughout and this is a great day for history, battlefield archaeology and Bosworth."