Devilling
Devilling is the period of training, pupillage or junior work undertaken by a person wishing to become an advocate in one of the legal systems of the United Kingdom or Ireland.
Scotland
The prospective advocate is placed under the care of a devilmaster, who traditionally must not be a Queen's Counsel. The pupil follows a programme of training as laid down by the Faculty of Advocates.
The process has an ancient heritage, as it is the legal right of the Faculty of Advocates to admit persons as advocates to the Courts of Scotland. This right was apparently granted by the College of Justice.
Ireland
Devilling is a period of training undertaken by barristers in Ireland, during which they work for a senior barrister (one who has been called for seven or more years but who is not a senior counsel), known as the "master". It can take place during the year after which the devil has been awarded the barrister-at-law degree by the King's Inns, although it may be done later.
In order to have full rights of audience in the Irish Courts, a qualified barrister must devil for at least one year. The work is generally unpaid, and there is no obligation on the Master to pay the Devil. A barrister who has not completed his devilling may still be recognised as fully qualified by the bar associations of other EEA member states, and practise in those member states in accordance with the relevant European Union (EU) directives.
England and Wales
The term is used in the English legal system to refer to a junior barrister undertaking paid written work on behalf of a more senior barrister. The instructing solicitor is not informed of the arrangement and the junior barrister is paid by the senior barrister out of his own fee as a private arrangement between the two. This is one of the exceptions to the usual prohibition on fee sharing under the Code of Conduct for Barristers in England and Wales.
Treasury Devil
The "Treasury Devil" is the colloquial term for the First Junior Treasury Counsel, a private practitioner barrister who represents Her Majesty's Government in the civil courts. The current Treasury Devil (2016) is James Eadie QC.