Bats and their roosts are legally protected in the UK under the Wildlife and Countryside Act 1981, making roost disturbance during building work a criminal offence.
Bats roosting in buildings face welfare threats from renovation and demolition that occurs without prior bat survey. Roost destruction during breeding season in June-August causes direct mortality of flightless young bats and displacement of nursing females during a critical welfare period. Legal protection is only effective when enforced and when planning processes require adequate survey before work begins. Roost displacement without mitigation forces bats to find alternative sites in sometimes unsuitable locations, increasing energy costs and exposure to predation. The welfare safeguard of legal protection depends on competent ecological survey identifying roosts before work begins.