The Bat Conservation Trust has published a guidance note entitled "Bats, Development and Planning in England," which seeks to provide an overview of the current planning framework with reference to bats. However, it does not give guidance to planners on the types of application for which they should consider asking for a bat survey to be undertaken before registration of the application, or as a condition attached to an approval. This document draws upon work done by the Durham Bat Group and the personal experiences of members of the Surrey Bat Group to provide such a list of criteria which we feel planners in Surrey should adhere to. Although written with Surrey in mind these criteria could be successfully applied in most counties of south-east England. The following types of structure should be surveyed before any work is approved involving demolition or modification to roof voids:

Pre-1960 detached buildings within 200m of woodland or water.

Pre-1914 buildings within 400m of woodland or water.

Pre-1914 buildings with gable ends and slate roofs, regardless of location.

All barns pre-1914 with exposed wooden beams greater than 20cm thick.

All tunnels, mines, ice-houses, military fortifications, air raid shelters and similar subterranean structures.

All bridge structures, aqueducts and viaducts (especially over water and
wet ground)

Proposals involving lighting of churches and listed buildings, or flood
lighting of green spaces within 50m of woodland, water, field hedgerows,
or lines of trees with obvious connectivity to woodland or water.

Proposals affecting woodland, or field hedgerows, or lines of trees with
obvious connectivity to woodland or water bodies.

All trees older than 100 years, or with obvious cavities, or with a girth greater than 1m at chest height.

Proposals affecting gravel pits or quarries and natural cliff faces and
rock outcrops with crevices, caves or swallets.

Proposals affecting or within 200m of rivers, streams, canals, lakes or
other aquatic habitats.

Proposed developments affecting any buildings, structures, features or
locations where bats are known to be present.

These criteria should cover the majority of scenarios, but bats are highly mobile animals and can turn up in unusual places. We believe these guidelines will aid planners in making initial decisions involving bats but they should not be used in isolation to rebut claims from the public that bats are roosting in structures that are the subject of planning applications.
Surrey has a number of private estates designated as Special Low Density Areas which contain substantial detached properties surrounded by mature plantings. These estates effectively constitute areas of houses within woodland, and there should therefore be a presumption in favour of surveys being undertaken in the majority of instances in which an older property is being demolished and re-built.