There are eighteen species of bat in Britain and all of them are endangered - though globally they are listed as 'Least concern' as numbers in other countries remain higher - though the IUCN's Red List has marked their population as 'declining'.
The greater horseshoe bat is one of the rarest in Britain. One reason for their decline is the destruction of suitable roosting sites, such as old buildings and hollow trees. Changing land use from woodland and small fields to large scale agriculture has also had an effect. They have also suffered from the use of insecticides (poisonous chemicals sprayed on to crops to kill harmful insects) which have deprived the bats of their insect food. Due to conservation efforts its population in the UK has stabilized at about 5000.