An otter has survived a "perilous" three-mile sea crossing to the Farne Islands for the first time, the National Trust has said.

The animal, more commonly found in rivers, has swum from the coast of Northumberland despite rough seas.

Head warden David Steel said he was stunned to find 60 yards of otter tracks on Brownsman Island, which is famed for its bird colonies.

The mammal has not yet been sighted, but it is thought to be still there.

Agitated behaviour by the island's gulls and puffins suggest the new predator has settled in.

While otters in Scotland do live in coastal areas, Mr Steel said it was "a rare event" to see them by the sea in England.

For one to reach an island three miles offshore was, he said, "incredible".