All UK bats are small and you may be surprised at the size. Baby bats are found in June, July or early August. At all other times of the year, the bats you see will be fully-grown and independent. Baby bats have little or no fur.
If you've found a baby bat you must get expert help as quickly as possible. There may be a bat rehabilitator near you who can assist. Call the Bat Helpline on 0345 1300 228 to find out.
In the meantime the bat should be contained.
Baby bats are very small and have greyish fur. When they are less than a week old they will not have any fur (see picture).
This is an adult pipistrelle; although it is still very small it is much furrier and quite distinct from a baby.