British Trust for Ornithology http://www.bto.org/
On line reporting form if you find a ringed bird http://www.bto.org/ringing/ringinfo/foundring.htm
Leicestershire & Rutland Ornithological Society http://www.lros.org.uk/
Rutland Water http://www.rutlandwater.org.uk/
Eyebrook Reservoir Ringing Group http://www.eyebrook.org.uk/
Dartford Ringing Group http://www.dartford-ringing.co.uk/
North West Norfolk Ringing Group http://www.nwnrg.co.uk/
Rye Meads Ringing Group http://www.rmrg.org.uk
Wash Wader Ringing Group http://www.wwrg.org.uk/
British Bird Observatories http://www.bto.org/ringing/ringinfo/observatories.htm
RSPB http://www.rspb.org/
Merseyside Ringing Group http://www.merseysiderg.org.uk/
Dean Birders (Disabled Forest of Dean birders) http://www.deanbirders.co.uk/
Banfield Wood Ringing http://www.andy67.freeserve.co.uk/