Image copyright Citizan Image caption Storms can expose archaeologically important sites overnight, which are at risk of being destroyed before they are recorded by experts

Archaeologists want to enlist the help of the public as they attempt to tackle what they describe as the "final frontier": England's coastline.

They hope to establish a network of volunteers around the nation to survey and monitor stretches of the shore.

Thousands of sites are being lost to the sea before they have been recorded by experts, they observed.

The three-year project is being hosted by a team from the Museum of London Archaeology (Mola).

"Our coastal and intertidal zone is our new frontier," explained project leader Gustav Milne from Mola.

This project is about part of our heritage that is unprotected and is being destroyed Gustav Milne, Museum of London Archaeology

"We have more or less sorted out things on land. We've sorted out the green frontier, now it is time to tackle the blue frontier - the final frontier."

The Coastal and Intertidal Zone Archaeology Network (Citizan) is looking for volunteers to help create a team of people that will be able to survey and monitor archaeologically important sites.

Image copyright Citizan Image caption The Citizan project hopes to establish a network of volunteers to monitor key sites around the coastline

"What we are trying to do is to train up, via archaeological societies, some people that have archaeological experience initially to become mentors so they can set up a small team in their area so then they can focus on a key site that they can survey and then monitor year-on-year," Mr Milne said.

"We are trying to embed an archaeological project in a particular locale, so its members will be able to recognise changes year-on-year.

"This project is about part of our heritage that is unprotected and is being destroyed."

Mr Milne explained that it was important to establish such a network because sites could appear without warning.

"It was like when we had those terrible storms in the 2013-2014 winter, when crumbling cliffs were cut back and silt was stripped off parts of the intertidal zone and new stuff was exposed," he told BBC News.

"Or it could be that stuff that was there was suddenly gone. We don't know when it is going to happen so that is why we need this constant survey monitoring."

Mr Milne said that a good example of the importance of having eyes on the ground was the sudden appearance of prehistoric burial mounds at a site in Northumberland.

"Because people were down there looking, they noticed these mounds being washed out of the cliffs," he recalled.

"We also keep finding fish traps, these large timber structures, which suddenly get exposed at low tide or after sudden erosion event."

Ben Greener, historic environment advisor for the Heritage Lottery Fund, which is funding the Citizan project, said: "Our coastlines are an enormous hidden repository of the remains of war defences, industry and ancient settlements providing a fascinating insight into the history of this island nation."

People interested in getting involved are being encouraged to visit the project's website.