There are about 16,500 barristers in practice in England and Wales, including about 3000 barristers employed by organisations such as the CPS, independent businesses, local government and the Civil Service
Barristers cannot turn down a case in their area of law if they are free to take it, except in direct access where they can turn down cases requiring investigation or support services they cannot provide
This body sets training and entry standards but also regulates the barrister's profession. It sets out a Code of Conduct that barristers have to comply with.
If a complainant is unhappy with the decision of the Bar Standards Board, a complaint can be made to the Legal Ombudsman.
liability
A barrister enters a contract with a client on the Direct Access scheme and such client can sue for breach of contract. A barrister can be liable in negligence for a poor quality of advocacy (but this must be more than just losing a civil claim or being convicted in a criminal case).