A dinosaurs’ graveyard of Britain’s maritime past emerges eerily from a mile and a half of bank along the River Severn.

Bleached blond ribs of once proud schooners, lighters, barges and Severn trows poke from the silt, still stained with pitch and the carmine of rusting iron nails. Above them loom abandoned concrete grain barges built during wartime when steel was in short supply.

The Purton hulks have become a magnet for naval historians, marine archaeologists and photographers enraptured by the weatherworn timbers and the tales they hold. But this unique repository of marine history is disappearing quickly, prompting the launch of a campaign to protect it.

The main problem is not the tidal waters of the Severn that take their toll at every high tide but human scavengers who, for more than 100 years, have been picking over the hulks for timber or valuable metals.

The vessels were abandoned along the Severn between Purton and Sharpness between 1909 and 1963.

In 1906 the bank had been damaged during storms and the Gloucester Sharpness ship canal, which runs parallel to the river, ran dry. The canal was rebuilt and an appeal was started for the owners of unwanted vessels to beach them to prevent the tides from eroding the bank again.

Over the next half-century, more than 80 vessels were run aground at high tide, creating what experts claim to be the world’s largest conglomeration of historic wooden vessels.

Paul Barnett, who first visited the site as a teenager in 1976, has watched the remains disappear as remorselessly as he has researched every vessel, its owners, crews and history. Albums of photographs record the transition from working boat, to stripped-out hulk, to little more than an outline in the grass. All that remains of theKatherine Ellen, seized by the Royal Navy after running guns to the IRA in 1921, is the rusty tube of her bilge pump. Others, such as the Harriett, a Kennet barge built in Pewsey in 1894, are intact, her name just visible on the stern.

Mr Barnett said: “Because the vessels were abandoned with no money changing hands they belong to no one. At first the locals used them as a free supply of timber for their fires. Then others came and salvaged the semiprecious metals such as the phosphor bronze pins that held them together.”

In 1986, he said, a youth set fire to nine of the hulks. “And it is still going on. I brought a group down here one Sunday and we found a family cooking over a barbecue made with ships’ timbers.”

Mr Barnett, who has raised a 1,000-signature petition, wants the site protected rather than preserved. He said: “Preservation would not be realistic but I’d like to stop the vandals and the people who come down to take bits away.”

The Severn Collier was one of the last Severn trows, working boats of which hundreds once plied the river.

David White, 71, who lives in a canal-side cottage near the boat’s last resting place, recalls replacing timbers and repitching her in the early 1960s when she was still in use. He said: “I was very sad when she was abandoned here. I always wanted her to go to a museum.”

One reason the site is unprotected is because it falls between the marine and the land environment. English Heritage says it is developing a national strategy to address such situations but it will not be completed until 2010.

But Mr Barnett said: “Every time I come here another little bit of history has vanished. How much more will have gone in two years’ time?”

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