The British Psychological Society is the representative body for psychology and psychologists in the UK. http://www.bps.org.uk
It has national responsibility for the development, promotion and application of psychology for the public good, and promotes the efficiency and usefulness of its members by maintaining a high standard of professional education and knowledge.
You may be interested to know that their Annual conference is soon to be held in the very pretty town of Stratford-upon-Avon.
The link for full details is here http://www.bps.org.uk/ac2010/