A species of bat never seen before in the UK has been discovered in caves in Yorkshire and Sussex.

Myotis alcathoe, or Alcathoe's bat, was found in woodland in Rydedale in the North York Moors National Park and the South Downs of Sussex.

The bats, which are about the size of the end of a thumb, were identified by researchers from Leeds and Sheffield universities.

It is believed they could be present in other parts of Britain.

The bats were found during a Europe-wide study of bat population ecology and genetics.

'Swarming' sites

The species was discovered in Greece in 2001 and is a native of continental Europe, but until now it was presumed that the English Channel had acted as a barrier preventing it from reaching the UK.

Researchers believe the bat has not been spotted before because its appearance is similar to other species.

Professor John Altringham, from the University of Leeds, said: "Most of the bats were captured as they entered underground 'swarming' sites, where bats gather to mate before going into hibernation."

He said the discovery took the number of bat species established in the UK from 16 to 17.

Brian Walker, Forestry Commission wildlife officer for the North York Moors, said: "We have some incredibly rich bat habitats in North Yorkshire.

"It was only a few years ago that work locally helped to confirm that the common pipistrelle was actually made up of two different species."