The right to trial by jury was suspended for certain "scheduled offences" and the court consisted of a single judge. The courts were abolished in 2007. However, the trial of Brian Shrivers and Colin Duffy for the murder of two British soldiers during a Real IRA gun attack on Massereene army base in Antrim town in 2009, was heard in a Diplock court in January 2012.
The courts were established in response to a report submitted to parliament in December 1972 by Lord Diplock, which addressed the problem of dealing with Irish republicanism through means other than internment. Lord Gardiner's Minority Report as part of the Parker Report in March 1972 found "no evidence of this or of perversity in juries". The report marked the beginning of the policy of "criminalisation", whereby the State removed legal distinctions between political violence and normal crime, with political prisoners treated as common criminals. The report provided the basis for the Northern Ireland (Emergency Provisions) Act 1973, which, although later amended (with the Prevention of Terrorism (Temporary Provisions) Act 1974 and subsequent renewals), continued as the basis for counter-terrorist legislation in the UK. Until recently the Diplock courts only tried Republican or Loyalist paramilitaries. In the first case in which a person not associated with the Troubles was tried and convicted, Abbas Boutrab, a suspected al-Qaeda sympathiser, was found guilty of having information that could assist bombing an airliner. A sentence of six years was handed down on December 20, 2005.
Diplock courts were common in Northern Ireland for crimes connected to terrorism. The number of cases heard in Diplock courts reached a peak of 329 yearly in the mid-1980s. With the Northern Ireland peace process that figure fell to 60 a year in the mid-2000s. On 1 August 2005, the Northern Ireland Office announced that the Diplock courts were to be phased out, and in August 2006 they announced that the courts were to be abolished effective July 2007. This was achieved under the Justice and Security (Northern Ireland) Act 2007.
Brigadier Frank Kitson 
The transition from Internment to Diplock Courts was the culmination of a series of proposals put forth by Brigadier Frank Kitson. Kitson’s work appeared to be a blend of sociological ‘normalisation’, political policy and legal plasticity. In Kitson’s book on counter-insurgency published in 1970, he advocated for the Courts to be used as another part of the Army’s arsenal in the fight against insurgents. He argued:
…the Law should be used as just another weapon in the government’s arsenal, and in this case it becomes little more than a propaganda cover for the disposal of unwanted members of the public. For this to happen efficiently, the activities of the legal services have to be tied into the war effort in as discreet a way as possible...
On the other hand, the establishment of the Diplock Courts can be seen as an early, and successful, example of PIRA's long-term aim of making 'the Six Counties... ungovernable except by colonial military rule'. This was one of the central pillars of the 'Long War' strategy set out in the 1977 'Green Book': while PIRA claimed its armed struggle sought to end British 'colonial' rule, its leadership realised that Catholic perception of British 'colonialism', and the subsequent disillusionment caused by this, was of great value in persuading the Catholic community to embrace the Republican cause.
Jury intimidation 
In his report, Lord Diplock, cited two primary reasons for his determination that jury trials should be suspended, 1) danger of perverse acquittals, and, 2) jurors had been threatened, "of which we have had ample evidence". Two years later Lord Gardiner’s review of the removal of trial by jury, included attempts to bolster Diplock’s findings as follows:
We are convinced on the evidence that we have received, that if juries were to be reintroduced for scheduled offences, their verdicts would still be subject to the influences of intimidation, or the fear of it. We have no evidence of this or of perversity in juries...
The Gardiner Report found that “no evidence” existed on which the removal of the jury was based but concluded that non-jury trials should continue.
List of famous cases tried in Diplock courts 
- Shankill Butchers
- Shankill Road bomber Sean Kelly
- The Christy Walsh Case
- The Milltown Cemetery attack
- The corporals killings
- Danny Morrison (writer)
- R v McCormick (1978) NI: Justice McGonigal ruled that slaps of the hand were permissible and not a form of torture or "degrading and inhumane treatment".
See also 
- Diplock Courts profile BBC news, 3 July 2007
- McDonald, Henry (20 January 2012). "Brian Shivers found guilty of Massereene murders". The Guardian.
- Report of the Commission to Consider Legal Procedures to deal with Terrorist Activities in Northern Ireland (Cmmd. 5185); full text of the Diplock Report
- Greer & White: Abolishing The Diplock Courts, page 91: Report of a Committee to consider, in the context of civil liberties and human rights, measures to deal with terrorism in Northern Ireland, Lord Gardener.
- Donohue, Laura (2007): Counter Terrorist Law and Emergency Powers in the United Kingdom 1922-2000, S. 155
- Al-Qaeda terror suspect convicted, BBC News Online, 24 November 2005
- Al-Qaeda terror suspect is jailed, BBC News Online, 20 December 2005
- "Two jailed for life for killing policeman Stephen Carroll". ITV News. 30 March 2012. "They were tried in a 'diplock court' by a judge with no jury; common in Northern Ireland for crimes connected to terrorism."
- PDF (494 KiB), Northern Ireland Office consultation paper, August 2006
- Jury trials 'to become the norm', BBC News Online, 11 August 2006
- Kitson cites Sir Robert Thompson, Defeating Communist Insurgency, page 53.
- See O'Brien, The Long War p.23
- Lord Diplock, Report of the Commission to consider legal procedures to deal with terrorist activities in Northern Ireland, para 37.
- Greer & White: Abolishing The Diplock Courts, page 91.
- British plan to abolish Diplock courts next year, The Irish Times, 11 August 2006
- Christy Walsh: a miscarriage of justice — from the British–Irish Rights Watch group
- In response to the serialisation of loyalist killer Michael Stone's book. - Relatives for Justice
- Corporals Derek Wood and David Howes
- Taylor, Peter (1999). Loyalists: war and peace in Northern Ireland. TV Books, p. 158. ISBN 1-57500-047-4