History
The conflict in Northern Ireland during the late 20th century is known as the Troubles. Over 3,600 people were killed and thousands more injured.
During this period the security forces were central to the conflict, with agencies from the British Army and the Royal Ulster Constabulary to MI5 and the SAS engaged in a 'dirty war' with paramilitaries.
Photo: British army soldiers patrol the streets of Belfast, Northern Ireland (大象传媒)
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A report by Chris Patten recommends changes to the police force in Northern Ireland.
A report by Chris Patten, chair of the Police Review Commission, recommends changes to the police force in Northern Ireland.
The relationship between the Royal Ulster Constabulary and the Army in Northern Ireland.
The relationship between the Royal Ulster Constabulary police force and the British Army during the conflict in Northern Ireland.
Barrie Penrose reports on the UDR, a British Army reserve force in Northern Ireland.
Barrie Penrose reports on the UDR, a part-time auxiliary force of the British Army in Northern Ireland.
British agencies began gathering covert intelligence on the IRA after Bloody Sunday.
British agencies began to gather covert intelligence on the Irish Republican Army in the wake of Bloody Sunday.
The longest military campaign in the history of the British Army comes to an end.
The longest military campaign in the history of the British Army comes to an end. Operation Banner began in 1969.
Troops arrive
It was like a scene from a war movie as thousands of British soldiers disembarked from ships in Belfast in the summer of 1969.
The small peacetime garrison in Northern Ireland was reinforced from army bases all over the world. Troops and equipment landed from throughout the United Kingdom, Germany and France. Many soldiers arrived with bayonets fixed. Some of the signs they carried warned rioters to disperse - in Arabic.
Military commanders thought their troops would be deployed for a few weeks. Operation Banner, the name given to the army's support role for the police during the Troubles, lasted for 38 years. It was the longest continuous campaign in the history of the British Army.
More than 300,000 British soldiers served in Northern Ireland during that campaign, with more than 500 members of the regular army killed. British Army soldiers themselves were responsible for the deaths of more than 300 people, over half of them civilians.
At the height of the Troubles in 1972, there were 27,000 military personnel in Northern Ireland, based in more than a hundred locations. That is a thousand more than the number of British soldiers deployed for the invasion of Iraq in 2003.
Worn-out welcome
Initially, the troops were welcomed by Protestants and Catholics and were viewed as protection against sectarian attacks. Soldiers were served tea and toast when they arrived in the Catholic Falls Road area of west Belfast.
But that soon changed. Within a few years, many Protestants came to view the army as their protectors against the Provisional IRA's violent campaign to force Northern Ireland out of the United Kingdom.
Many Catholics began to see the army as an oppressive force supporting unionist rule.
The key catalyst for this change in perception was the killing of 13 Catholic civilians by members of the Parachute Regiment in Londonderry on 30 January 1972.
Police
The army was deployed because Northern Ireland's police force, the Royal Ulster Constabulary (RUC), was at breaking point and unable to contain the violence on the streets.
The RUC was formed after the creation of the state of Northern Ireland in 1922, when the unionist government feared cross-border attacks or an internal IRA insurrection. It was an armed police force with the dual purpose of defending the state and maintaining law and order.
This police force was regarded by many Catholics as the armed wing of unionism. At the outset, one third of its 3,000 places were reserved for Catholics, but the numbers who actually joined its ranks averaged just 8%.
The unionist government also recruited an all-Protestant militia called the Ulster Special Constabulary ("B Specials"), which only served to reinforce Catholic alienation from the police.
Despite its reliance on the RUC to protect the state, the government of Northern Ireland failed to invest in training and equipment. This resulted in the police being stretched to breaking point by a series of civil rights marches, counter-demonstrations and serious disorder.
In August 1969, sectarian violence erupted in Belfast, while in Derry nationalists fought running battles with the police. The situation was desperate, prompting the British government to send in troops to prevent further trouble.
Reserve force
The B Specials were deeply unpopular with the Catholic community and were disbanded in 1970 as part of local government reforms. They were replaced by the Ulster Defence Regiment (UDR). It recruited from across the entire community, but few Catholics signed up and many of those who did quickly left because they were targeted by the Provisional IRA (PIRA).
While Protestants viewed the UDR as a vital bulwark in the battle against the IRA, many Catholics viewed it as unionist militia. The regiment gained a notorious reputation when some of its soldiers became involved in serious terrorist activity, including murder.
Members of the RUC and UDR were exposed to huge risks in the course of their duties. More than 300 RUC officers and over 200 members of the UDR were killed during the Troubles.
Battle for supremacy
The police and army were supposed to work together, but from the outset there was open hostility and rivalry about who should take the lead role. It was not until 1976 that the RUC was given primacy and took the lead in conducting anti-terrorist operations, with soldiers deployed in support of police officers rather than conducting their own operations.
Members of the British special forces, in particular the Special Air Service (SAS), were also deployed, sometimes in highly controversial circumstances. On a number of occasions they were accused of operating a "shoot-to-kill" policy, firing on terrorists or suspected terrorists instead of arresting them.
The Security Service (MI5) was also heavily involved in Northern Ireland during the Troubles, carrying out surveillance and running its own network of agents and informers within republican and loyalist paramilitary organisations.
Collusion
All sections of the security forces operating in Northern Ireland during the Troubles faced allegations of collusion with members of loyalist paramilitary organisations. In recent years, investigations have concluded that collusion did take place, resulting in a number of murders.
Perhaps the most notorious case is that of the killing of Belfast solicitor Pat Finucane. An independent review in 2012 concluded that agents of the state were involved in the brutal 1989 murder and that it could have been prevented, prompting an apology from British Prime Minister David Cameron.
Post-peace policing
Much has changed. As a result of the peace process, the RUC was replaced by the Police Service of Northern Ireland (PSNI) in 2001, with legislation directing that 50% of all new recruits had to be from the Catholic community for the first 10 years of its existence. Currently, around 30% of its officers are Catholics.
The PSNI enjoys record levels of consent and co-operation from Protestants and Catholics, despite a continuing threat from dissident republicans opposed to the political process and persistent public disorder in some republican and loyalist communities. Dissident republicans have killed two PSNI officers in recent years.
For the British Army, Operation Banner ended in the summer of 2007, nearly four decades after soldiers arrived. In future there will be no more than 5,000 British soldiers based in Northern Ireland, to be deployed in foreign trouble spots, not on local streets.
MI5 still operates in Northern Ireland and has primacy when dealing with national security issues, such as the continuing threat from dissident republicans.
Vincent Kearney was writing in February 2013