E.g. Engineering Employers' Federation:
EEF is a trusted partner to businesses across Britain. We provide our members with business advice, resources and support services to help them operate more effectively and help them tackle a whole range of employment issues.
http://www.eef.org.uk/UK/default.htm
e.g. Police Federation of England and Wales:
The Police Federation of England and Wales is the staff association that represents all 140,000 police officers up to and including the rank of Chief Inspector. We have a statutory obligation to ensure that the views of our members are accurately relayed to government, opinion formers and key stakeholders. To ensure this we measure the work we do and what we seek to achieve against our organisational aims and objectives.
http://www.polfed.org/
e.g. British Medical Association (BMA)
They are the independent trade union and professional association for doctors and medical students, with over 140,000 members worldwide.
http://www.bma.org.uk/