The British Government under Prime Minister Harold Wilson ordered the deployment of troops to Northern Ireland in August 1969. This was to counter the growing disorder surrounding civil rights protests and an increase in sectarian violence during the traditional Protestant marching season.
The Roman Catholic population of Northern Ireland had little faith in the Royal Ulster Constabulary (RUC), which it perceived as a pro-Protestant organisation. It was hoped that the British Army would not only help restore order but also be regarded as a more acceptable peacekeeping force.
Although the Army came under the control of the Secretary of State for Defence in London, many Catholics saw it as a tool of the Unionist Government in Northern Ireland. As a result the Provisional Irish Republican Army (PIRA), formed in 1969 and with its membership growing, increased levels of violence against both the police and the Army.
Loyalist paramilitary groups including the Ulster Volunteer Force (UVF) and the Ulster Defence Association (UDA), intent on keeping the Province part of the United Kingdom, also stepped up their campaign of sectarian violence.
The early 1970s saw major rioting on both sides of the religious divide. The Army's initial troop deployment proved insufficient and required reinforcement. The British tactic of operating and patrolling from fortified bases in the major towns, developed during these early years, set a pattern for the next 30 years.
By June 1971 the situation had deteriorated after the killing of three soldiers and the shooting dead of two men by the Army. In August protest and violence increased with the introduction of internment: the arrest, interrogation and detention of Republican suspects without trial. The policy proved counter-productive as it hardened legitimate opposition and bolstered support for the PIRA, particularly in the Catholic housing estates of Belfast and Derry.
On Sunday, 30 January 1972, a march organised by the Northern Ireland Civil Rights Association became the focus of international attention when British troops killed 14 people and wounded another 13. The events surrounding 'Bloody Sunday' were disputed for years and in 1998, after years of protest and an earlier inquiry, the British ordered a full-scale judicial inquiry.
In June 2010 it concluded that the soldiers on duty had 'lost control' and opened fire without warning and did so before they had come under fire from Republican gunmen. 'Bloody Sunday' swelled the ranks of the IRA, civil unrest continued and violence against the security forces increased. In February 1972 Aldershot barracks were bombed by the PIRA in retaliation, and six civilians and an Army chaplain killed.
In the Province troops and vehicles on patrol, undertaking searches and acting as snatch squads, increasingly came under attack from terrorists and rioters using petrol and nail bombs. In urban areas riot gear became an integral part of the British soldier's kit as were rubber bullets, controversially used against rioters. The Army's urban warfare skills were honed as they had to counter the threat of snipers, booby traps, mortars and bombs.
In the countryside, particularly South Armagh's 'bandit country', the risk of ambush contributed to the Army's reliance on helicopters to both reconnoitre and ferry troops. The Army operated a 'tour of duty' policy for troops. The advantage of this was that troops had an end in sight and their exposure to stress and danger was limited in duration. The disadvantage was that the build-up of experience and local knowledge could be curtailed and the benefits of continuity lost.
In July 1972 the Army carried out Operation Motorman, an attempt to regain control of 'no-go areas' primarily in Derry and Belfast. 1972 saw the resignation of the Northern Ireland Government and a return to direct rule from Westminster. Further attempts at creating devolved government in the Province foundered with the Unionists staunchly resisting the idea of power sharing.
The PIRA, with a steady supply of arms and money from sympathisers in the Republic of Ireland, USA and elsewhere, continued to target security forces and economic targets, increasing its campaign on mainland Britain. The bombing campaign of 1974 included attacks on pubs in Birmingham, Guildford and Woolwich in which many civilians died alongside off-duty soldiers.
On 27 August 1979 the PIRA killed 18 soldiers from the Parachute Regiment and the Queen's Own Highlanders in a ruthless ambush at Warrenpoint. The same day also witnessed the murder of Lord Louis Mountbatten at Mullaghmore in the Republic of Ireland.
The death of 10 Republican prisoners on hunger strike, protesting for political status, greatly increased support for PIRA and its political wing, Sinn Fein. Throughout the 1980s, as Sinn Fein attempted to gain political influence, PIRA and other groups such as the Irish National Liberation Army (INLA) continued their campaign of violence. In July 1982 11 soldiers from the Blues and Royals and the Royal Green Jackets were killed in two bomb attacks in London.
In October 1984 five people died when an attempt was made to murder Prime Minister Margaret Thatcher and her cabinet at the Conservative Party Conference in Brighton. As Anglo-Irish co-operation increased Republican terrorists killed 11 people at Enniskillen's war memorial during the Remembrance Sunday service in 1987.
As the numbers of troops deployed in the Province fluctuated counter-terrorist action by the British Army and intelligence agencies was stepped up. In 1987 eight terrorists were killed in an ambush at Loughall, and in the following year the Special Air Service (SAS) killed members of a PIRA active service unit in Gibraltar. British forces suffered many casualties in 1988 and 1989, the most severe being the killing of 10 Royal Marines in a bomb at the Royal Marines School of Music at Deal in Kent.
By the early 1990s the PIRA began to concentrate on civilian targets on the mainland, including a large bomb in the City of London. Talks between John Hume, leader of the Social Democratic and Labour Party and Gerry Adams of Sinn Fein, along with secret contacts with the British Government formed the basis for a new peace initiative. Sectarian violence continued to increase but on 31 August 1994 the PIRA announced a cease-fire that was followed in October by a similar announcement by Loyalist paramilitaries.
In 1996 with talks over decommissioning under way, the PIRA resumed its terrorism campaign with the detonation of a major bomb at Canary Wharf in London. The cease-fire was re-established in 1997 and further talks resulted in the 'Good Friday Agreement' in April 1998. The agreement was announced by all the main parties except the Democratic Unionist Party and was backed by referenda north and south of the border.
It marked a return to devolved government in the Province with the establishment of a power sharing administration. An integral part of the agreement was the cessation of paramilitary violence and the de-commissioning of stocks of illegal arms. British Army numbers and installations in the Province were reduced and security procedures gradually relaxed.
Although the process of normalisation has continued, sectarian violence and paramilitary crimes continue in Northern Ireland and a threat to security still exists from paramilitary splinter groups like the Real IRA. The worst example of continued terrorist action was the Omagh bombing in August 1998 that killed 29 people.
Sir Kenneth Bloomfield's Northern Ireland Victims Commission 1998 report 'to look at possible ways to recognise the pain and suffering felt by victims of violence arising from the troubles of the last 30 years' referred to over 3,600 deaths during the course of 'The Troubles'.