Divers are joining a "neighbourhood watch for the sea" as efforts are stepped up to protect thousands of shipwrecks off Kent.
The bid to preserve the marine environment comes as UK police forces focus more on heritage crime.
Each force has a heritage crime lead and thieves face stiffer jail terms.
But, the only way shipwrecks could be policed was for people to report suspicious activity, Historic England's (HE) policing advisor explained.
Mark Harrison said the English Channel was like a "ships' graveyard" with thousands of wrecks on the sea bed - following two world wars and centuries of seafaring.
Mr Harrison, who used to work for Kent Police and spearheaded a partnership to tackle heritage crime across England, said criminals were a tiny minority but most people, including divers and people living along the coastline, wanted to help.
"If we can get the Kent coastline up and running as a heritage watch area, really that's the only way we can do it," he said.
Jane Maddocks, of the British Sub-Aqua Club, said divers formed personal attachments to wrecks, wanted to protect them, and were happy to report any suspicious activity.
'A different world'
She said: "The sea is going to damage the wrecks. But, the divers make sure it isn't gratuitous damage.
"We are aware that wrecks are disintegrating, some quite quickly. But if we don't look after them what will people see?"
She said exploring wrecks took people into a different world.
"You don't see the wreck - you remember its story, how it happened, whether there were any survivors," she said.
"It can be ghostly. A couple of wrecks are very spooky."
According to HE, there are about 50 protected wrecks in the English Channel, including 32 protected for their historic interest, plus several military wrecks that are designated war graves. However, it is understood there are nearly 7,500 lying in the area.
Heritage protection adviser Mark Dunkley said people were targeting wrecks from both the UK and Europe but UK authorities had no jurisdiction to impound foreign vessels taking divers to sites.
He said people could remove items from shipwrecks if they followed proper procedure and reported them to the Receiver of Wreck.