Direct rule was seen as a temporary measure until devolved government could be re-established.
The Northern Ireland Assembly Act of May 1973 restored devolved government and elections - boycotted by republicans - were held on 28 June.
Abolition of Stormont
The Northern Ireland Constitution Act, meanwhile, received Royal Assent on 18 July. This abolished the suspended Stormont Parliament and established the principle that only a majority of the Northern Ireland electorate could alter its constitutional status.
The Northern Ireland Assembly met for the first time on 31 July, and following the Sunningdale Agreement a power-sharing Executive was established from 1 January 1974.
February 1974 election
In the general election of February 1974, 11 out of 12 constituencies in Northern Ireland were won by the United Ulster Unionist Council, a coalition of anti-Sunningdale Unionists. Only West Belfast returned a pro-agreement MP.
The Ulster Workers Council then called a general strike, and on 28 May 1974 the Northern Ireland Assembly and Executive collapsed.
For the next 20 years the UK government and Parliament was preoccupied by violence from Republican and Loyalist paramilitary organisations.
Airey Neave MP killed
Occasionally there were attacks on Parliament itself. On 30 March 1979 the Conservative MP Airey Neave was killed as he drove out of the Palace of Westminster car park.
During the hunger strikes by IRA prisoners in 1981 Bobby Sands, the strike’s leader, was elected to the House of Commons in a by-election.
Parliament soon passed the Representation of the People Act, which prevented certain prisoners from being nominated as candidates in UK elections.
Failure to reach consensus
There were periodic attempts to revive devolved government, for example the Northern Ireland Constitutional Convention (1975) and a second Northern Ireland Assembly (1982-86), but all failed to reach consensus or operate for any length of time.
In 1986 the UK and Irish governments signed the Anglo-Irish Agreement, a formal partnership which would seek a solution to the problems in Northern Ireland. Peace, however, remained elusive for more than another decade.