All UK bat species are legally protected, and disturbing roosts or killing bats is a criminal offense, but development pressures and roost destruction remain significant welfare threats.
Bats disturbed in roosts during hibernation deplete critical fat reserves that may cause death before spring. Roost destruction during breeding season kills dependent young that cannot survive independently. Bats are long-lived social animals with complex echolocation-based perception of the world - the loss of roost sites represents genuine welfare harm and population impact combined. The legal protection framework is strong but enforcement depends on adequate surveying before development proceeds.