Sir John Frank Mummery DL (born 5 September 1938) is a former Lord Justice of Appeal and is President of the Investigatory Powers Tribunal and member of the Court of Ecclesiastical Causes Reserved in the UK.
By the 1970s he was known as a copyright barrister, being consulted on matters such as Led Zeppelin's Black Mountain Side and its relation to Bert Jansch's version of Down by Blackwaterside. He also represented Apple Corps in efforts to stop the distribution of recordings of The Beatles in Hamburg.
He was appointed a recorder in 1989 before being appointed a High Court judge on 4 October the same year. He was assigned to the Chancery Division and received the customary knighthood. He was appointed a Lord Justice of Appeal on 1 October 1996. He served as President of the Employment Appeal Tribunal from 1993 to 1996, and was appointed President of the Security Services, Intelligence Services and Investigatory Powers Tribunals in 2000. He reached mandatory retirement on 5 September 2013. He has, since 2003, been Chairman of the Trustees of the Royal Courts of Justice Citizens Advice Bureau.
From 2000 to 2003, he served as Chancellor of the Inns of Court, and was from 1996 to 2001 a governor of the Inns of Court School of Law. He has been a member of the Legal Advisory Commission of the Church of England since 1988 and Chairman of the Clergy Discipline Commission and Clergy Discipline Tribunal since 2004. He is also a judge of the Court of Ecclesiastical Cases Reserved, having served in that role since 2006.
Notable cases in which Mummery LJ has been involved include:
- Clark v TDG Ltd (t/a Novacold Ltd) (1999)
- Re Barings plc (No 5) (1999)
- O'Neill v Phillips (1999)
- Hollicourt (Contracts) Ltd v Bank of Ireland (2000)
- Peskin v Anderson (2001)
- Copsey v WWB Devon Clays Ltd (2005)
- Redfearn v Serco Ltd (2006)
- Collier v P & MJ Wright (Holdings) Ltd  EWCA Civ 1329,  1 WLR 643 - English contract law concerning the doctrine of consideration and promissory estoppel in relation to "alteration promises".
- Luke v Stoke County Council (2007)
- Moore Stephens v Stone Rolls Ltd (2009)
- Revenue and Customs Commissioners v Annabel’s (Berkeley Square) Ltd (2009)
- Gisda Cyf v Barratt (2010)
- Link Lending v Bustard (2010)
In 2017, he was awarded The Canterbury Cross for Services to the Church of England by the Archbishop of Canterbury.
- Law Report 28 October 1975 Court of Appeal, 'Similar facts' admissible in copyright action, Mood Music Publishing Co Ltd v De Wolfe Ltd
- The Times, 7 April 1977: Chancery Division No injunction to stop alleged offence, Apple Corps Ltd and Others v Lingasong Ltd and Another
- "No. 51895". The London Gazette. 9 October 1989. p. 11545.
- "No. 54543". The London Gazette. 4 October 1996. p. 13211.
- "The Rt Hon Sir John Mummery DL". Debrett's People of Today. Retrieved 21 October 2012.
- "Archbishop of Canterbury's Awards ceremony held at Lambeth Palace". Archbishop of Canterbury. 13 June 2017. Retrieved 14 July 2017.