A brief history of how lay assistants came to be called McKenzie Friends.
McKenzie v McKenzie an English divorce case. Levine McKenzie, who was petitioning for divorce, had been legally aided but the legal aid had been withdrawn prior to the case going to court. Unable to fund legal representation, McKenzie had broken off contact from his solicitors, Geoffrey Gordon & Co. However, one day before the hearing, Geoffrey Gordon & Co sent the brief for the case to an Australian barrister in London, Ian Hanger, whose qualifications in law in Australia did not allow him to practise as a barrister in London. Hanger hoped to sit with his client to prompt him, take notes, and suggest questions in cross-examination, thereby providing what quiet assistance he could from the bar table to a man representing himself. The trial judge told Hanger that he must not take any active part in the case, which Hanger interpreted as an order to desist from doing what he was doing.
The case went against McKenzie, who then appealed to the Court of Appeal (McKenzie v McKenzie  3 WLR 472 CA) on the basis that he had been denied representation. On 12 June 1970 the Court of Appeal ruled that the Judge's intervention had denied McKenzie of assistance to which he was entitled, and ordered a retrial.
Ian Hanger, the original McKenzie friend, went on to become a QC at the Queensland Bar