Archaeologists are losing the fight to save Britain's battlefields from the mounting destruction wrought by armies of metal detectorists, farmers and developers.
Experts have called on the government to bring in legislation to defend the sites where many of the most significant episodes of the country's history were recorded in the earth.
A session of the Institute of Field Archaeologists' annual conference at Liverpool University this week heard that charting the scatter of arrowheads and musket balls across contemporary landscapes could provide vital clues as to how engagements were fought. Recent investigations at Naseby, where a key engagement in the English Civil War was fought in 1645, and Towton, site of the 1461 War of the Roses clash renowned as the bloodiest fought on English soil, are already rewriting history on the basis of such evidence.
Yet much is being lost, largely to a minority of metal detectorists who strip fields of evidence, often with landowners' consent.
Glenn Foard, project officer at the Battlefields Trust, said English Heritage's review of the system to conserve the historical environment should raise the level of protection afforded to battlefields. "They are under terminal threat. If something is not done pretty soon, it will be too late for many," he said.
Interest in the systematic investigation of battlefields is still in its infancy in the UK after being largely ignored by the archaeological community. But the prospect of alerting metal detectorists to the precise location of potential finds is making leading figures nervous about the consequences of publishing their results.
The alarm was raised last year at Marston Moor, where the greatest battle of the English Civil War took place in 1644. Within weeks of a systematic reappraisal of the battlefield being published - among the first such surveys in the UK - a metal detectorist rally was organised to scour newly identified sites. About 300 people took part, and experts fear that an enormous amount of evidence went unrecorded.
Other remains are being threatened by farming, as agricultural techniques and the use of chemicals can destroy evidence in the ground. Developers are also looking to build on sites.
A planning inquiry saved the site of the War of the Roses battle of Tewkesbury, but the site at Fulford in Yorkshire, where a Viking army defeated a Saxon force in 1066, could soon be covered with housing - as was the fate of much of Stamford Bridge, where King Harold beat the Vikings later in the same year.
The Battlefields Trust's database records some 300 sites of conflict. The English Heritage battlefields register covers 43 but does not provide any statutory protection.
Tim Sutherland, an archaeologist who will also speak at the IFA conference, said this was wholly inadequate. He witnessed last year's legal rally held on the site of Marston Moor with the landowner's permission.
"I stood and watched as a battlefield was raped by 300 metal detectorists," he said.
Both Mr Sutherland and Dr Foard acknowledge the essential role that more scrupulous metal detectorists play in helping uncover the history of battlefields.
But Mr Sutherland fears that his PhD thesis on Towton - which revises our understanding of the key conflict - could prompt another Marston Moor when it is published. "I'm trying to prolong its production in the hopes that protective legislation will be introduced first," he said.