The right of an advocate to be heard in legal proceedings. Barristers have full rights of audience in all courts. Traditionally, solicitors only appeared in the county courts and magistrates' courts but they may now obtain higher rights of audience in the Crown Court, the High Court, the Court of Appeal, and the House of Lords. Many administrative tribunals have no rules concerning rights of audience and a party may be represented by any person he chooses.
http://www.barcouncil.org.uk/guidance/rights-of-audience/ Quick guide to rights of audience from the Bar Council website