All species of bat are legally protected in England and Wales and are covered by the Wildlife and Countryside Act 1981. It is an offence to try and kill or remove bats and you could be fined up to £5000 per incident or bat. Courts can even impose up to six months in prison. Even if bats have left your attic, it is still an offence to block the roost – bats return to the same place every year and so empty bat roosts are also protected.
If you suspect your loft, cellar or basement has bats there are certain things to look out for. The most obvious sign of a bat presence are droppings, these can vary in size and normally crumble in your fingers. The droppings may follow lines against beams or the edge of walls where the bats roost. Bats often chatter during the day so you may actually hear them or even be lucky enough to see one.
If you have found evidence of bats it may be re-assuring to know that they do not generally cause any damage to buildings, they will just leave a mess with their droppings. You will need to consult with the Bat Conservation Trust about treatment and they will recommend the next course of action.