Differences between British and U.S. usage: In English law, a brief is a document by which a solicitor instructs a barrister to represent a client in court.
There is a definition in the Oxford Dictionary of Law, edited by Elizabeth A. Martin, ISBN 0 19 860399 1, a paperback that has not much increased in size since it used to be called the Concise Oxford Dictionary of Law. Here’s the complete quote via xrefer:
bq. brief
A document by which a solicitor instructs a barrister to appear as an advocate in court. Unless the client is receiving legal aid, the brief must be marked with a fee that is paid to counsel whether he is successful or not. A brief usually comprises a backsheet, typed on large brief-size paper giving the title of the case and including the solicitor’s instructions, which is wrapped around the other papers relevant to the case. The whole bundle is tied up with red tape in the case of a private client and white tape if the brief is from the Crown.
Dictionary of Law, Oxford University Press © Market House Books Ltd 1997
(So the Oxford Dictionary of Law can be consulted online, together with a number of other sources).
‘Brief-size paper’ is rather a circular definition. It used to be paper twice as wide as the normal foolscap, typed on on a huge typewriter. We used to call the red tape ‘pink tape’ (see entry on stationery). A vague idea can be obtained from the picture at the mysterious Virtual Chambers site. Continue reading →