The northernmost Anglo-Saxon coin found in the UK has been discovered in Shetland, say archaeologists.

A group of archaeologists and detectorists uncovered the crux penny - which dates from the late 10th Century - in Nesting, part of the east Shetland Mainland.

The find suggests possible trading routes between Viking-controlled Shetland with Anglo-Saxons in England, or that it could be treasure from a Norse raid.

The coin depicts Ethelred II who was better known as Ethelred the Unready because he was unable to prevent Viking invasions of England.

The coin was discovered during a dig led by Archaeology Shetland and involving the University of Aberdeen.

The university's Dr Elinor Graham, who specialises in excavating eroding coastal sites, told BBC Radio Scotland's Good Evening Shetland programme: "The writing is still so sharp and we knew immediately that it was extremely rare, actually unique in this context."

Graham said one other Anglo-Saxon coin had previously been found in Shetland, at Old Scatness, an Iron Age broch and village in the isles' South Mainland.

The site at Nesting is further north.

Graham hopes the new discovery is added to the collections at Shetland Museum and Archives following analysis by the University of Aberdeen.

Scotland's Treasure Trove Unit decides whether finds should be offered to museums.

Graham said the coin suggested the local area may have had "well connected cosmopolitan community" with possible long distance trading links to the Anglo Saxon world.

"It's an area with a huge amount of history through the Bronze Age, the Iron Age, the early medieval period and into the Viking Norse period," she said.

Graham was on holiday in Shetland when she took part in the dig.

She said: "This is exactly how I wanted to spend my holiday."

Ethelred took over the English throne when he was aged about 12 years old in AD978 after the assassination of his half-brother, Edward, possibly at the instigation of his mother.

His turbulent reign reached its lowest point when he was briefly ousted from the throne by the King of Denmark, Sweyn Forkbeard, in 1014 before taking back power for two more years.

Ethelred tried to pay protection money to Viking raiders to stop them from attacking, but it proved ineffective.

While history remembers his nickname the "unready", which was a pun on his name, meaning "noble counsel", Ethelred was the longest-reigning Anglo-Saxon monarch.