For many years, probably for centuries, bats have hunted and roosted in churches. They have now become less than welcome. In the eighteenth and early nineteenth centuries, a church in Bedfordshire placed a bounty of 6d per dozen on the heads of the animals, and in the 1930s the organist of Binsey found himself unable to distinguish the black keys from the white because the colours were obscured by bat droppings. The problem, therefore, is not new. More recently, a debate in the House of Lords, initiated by Lord Cormack, a former Second Church Commissioner, produced a short-lived but vigorous spate of articles and letters in the national press. Complaints about the activities of bats came from far and wide, from North Yorkshire to Northampton and Oxford. The problem seems to be especially acute in East Anglia, however. The greatest cause for complaint was the damage caused to woodwork, floor tiles, alabaster memorials and monumental brasses by faeces and urine. As a moment's reflection shows, these are corrosive (the latter more so) and the effects can be disastrous. In any case, where bats are present in any numbers, someone has the distasteful task of trying to remove the droppings and the urine stains on pews, window sills and floors each time the church is used. It is not unknown for bats to defecate on the heads of incumbents at the altar, which raises questions as to the consequences of bat infestation for the health of clergy, congregations and other church users, over and above the damage to buildings and their contents.