UK bats and their roosts are legally protected under European Protected Species legislation, and development projects must survey for and protect bat roosts or risk criminal prosecution.
Bat roost legal protection creates a framework where individual bat welfare is legally protected at the point of roost disturbance - an unusual situation where wildlife welfare is specifically actionable in planning law. Bats disturbed from maternity roosts during the breeding season face welfare crises: flightless pups separated from mothers, temperature-dependent pup survival compromised, and adult bats stressed by disturbance of an otherwise stable resting environment. The legal protection creates strong incentives for developers to conduct proper surveys and implement appropriate mitigation, but enforcement of roost protection conditions is variable and the quality of mitigation provided in licensing conditions requires ongoing scrutiny.