ENGLAND
Environment Agency [England & Wales] http://www.environment-agency.gov.uk/
Natural England http://www.naturalengland.org.uk/
NORTHERN IRELAND
Northern Ireland Environment Agency http://www.ni-environment.gov.uk/
Council for Nature Conservation and the Countryside (CNCC) [Northern Ireland] http://www.cnccni.gov.uk/
Natural Environment Unit, DOE [Northern Ireland] http://www.doeni.gov.uk/index/protect_the_environment/natural_environment.htm
SCOTLAND
Scottish Environment Protection Agency (SEPA) http://www.sepa.org.uk/
Scottish Natural Heritage (SNH) http://www.snh.org.uk/
WALES
Environment Agency [England & Wales] http://www.environment-agency.gov.uk/
Countryside Council for Wales http://www.ccw.gov.uk/