The 4 Inns of Court are historic wonders – and modern day societies. They were founded after Edward I made an order in 1292 in Council. In order to become and stay a barrister, you have to join one of the Inns and be called to the Bar by it. Until you are called you cannot practise as a barrister.
The Inns contain buildings for the use of barristers – the Hall, bar, church, and library, and also buildings rented by sets of chambers. All barrister must be self-employed, but most join a set of chambers to share overheads such as clerks, utilities, books, experience, and for company. They also accept new barristers in the final stages of qualifying, pupils, in a type of apprenticeship.