A rare spider that was feared extinct in the UK has been caught on camera for the first time after a new colony of the species was found, experts have said.
The elusive Rosser's sac spider had not been seen in Britain for 10 years, but a colony has now been discovered at Chippenham Fen in Cambridgeshire.
The spider, Clubiona rosserae, which makes its home in wetland areas, has only ever been found in one other site in Britain, at Lakenheath Fen in Suffolk.
The light brown spider was first discovered in the 1950s, but the draining of the fens and changing farming practices since the Second World War has been putting its preferred habitat under threat, experts said.
Despite intensive searching in recent years by the British Arachnological Society and invertebrate charity Buglife, no spiders had been seen since 2000 and fears were growing that it had died out in the UK.
Then spider enthusiast Ian Dawson spotted a Rosser's sac spider in September at the Cambridgeshire site, and a further search in October revealed 10 spiders.
He said: "I was extremely surprised to find the first one and then when we went back a month later it was great to find more of them."
Buglife chief executive Matt Shardlow said: "This spider is globally endangered. It's fantastic that it's still creeping around in the British countryside and we're ecstatic that people can now see what it looks like for the first time in history.
"If we want future generations to be able to see the live animal, we will need to take great care of the tiny remaining fragments of wild wetlands in this country and reinstate large areas of lost fen."
Mike Taylor, of Natural England, which manages the Chippenham Fen reserve, said: "Rosser's sac spiders spend their days hidden in tubular silken retreats, often in a folded leaf, a bit like a sleeping bag."