Policy information sourced from the Hillingdon Local Plan: Part 1

EC2 Nature Conservation Considerations and Ecological Assessments

The local planning authority will promote nature conservation as a positive land use and will take nature conservation interests into account in considering proposals for development of land especially within sites of borough (grade II) and local importance, as defined by the london ecology unit. The protection of species afforded by the wildlife and countryside act 1981 (amended 1985) will be a material consideration. Where appropriate the local planning authority may ask applicants to submit an ecological assessment before it determines development proposals. 

For more information please see Appendix 5 of the Local Plan: Part 1