Sinn Fein splits Sinn Fein Ard Fheis divides into Officials and Provisionals on January 11, mirroring the December split in the IRA.

Political change Five Unionist MPs - Boal, McQuade, Craig, West and Laird - are expelled from the the Ulster Unionist parliamentary party in March.

Rev Ian Paisley

The following month, the Rev Ian Paisley and the Rev William Beattie win Bannside and South Antrim Stormont by-elections for the hardline Protestant Unionists.

In June, Paisley wins North Antrim from the Ulster Unionists at the Westminster general election which returned the Conservatives under Edward Heath to power in London.

MP Bernadette Devlin begins a six-month jail term in June for her part in the Bogside riots of 1969.

In August, the SDLP is formed under the leadership of Gerry Fitt.

Maudling New British Home Secretary Reginald Maudling visits Northern Ireland in June and has talks in London with Northern Ireland PM James Chichester-Clark later in 1970.

In August, he threatens direct rule from Westminster if reforms are not carried out.

Parades banned A six-month ban is imposed in July.

Rubber bullets are introduced by the Army in August.

Haughey trial

Haughey, cleared of arms smuggling

The former Irish Republic Finance Minister, Charles Haughey, is cleared of arms smuggling by a Dublin court in October. Another minister, Neil Blaney, was cleared in July. Both had been sacked by Taioseach Jack Lynch when charged in May.

Army deaths

Robert Curtis

Gunner Robert Curtis becomes the first British soldier to die in Northern Ireland since troops were brought in to aid the civil authorities. He is killed by machine gun fire in the New Lodge Road in February 1971.

The following month, the Provisional IRA kills three soldiers at Ligoniel.

New leader Stormont Prime Minister Chichester-Clark resigns in March, saying there was "no other way" of to bring home "the realities of the present constitutional, political and security situation."

Brian Faulkner wins the vote of Ulster Unionist MPs to succeed him.

Internment Violence escalates through summer 1971. On August 9, Army squads arrest 342 republicans and nationalists in dawn raids.

Just over 100 are released two days later, the rest are interned without trial. The violence redoubles in Belfast and Derry, resulting in thousands of families being forced to move.

Opposition politics In July, SDLP and Nationalist MPs withdrew from Stormont. After internment, they announce civil disobedience campaign and Gerry Fitt complains to UN Secretary General U Thant about brutal treatment of Catholics.

In October, Fitt is elected president of an alternative assembly. US Senator Edward Kennedy calls for British withdrawal and a united Ireland.

DUP Ian Paisley and William Boal form the Democratic Unionist Party in October. Paisley predicts direct rule.

McGurk's Bar Bomb In the worst incident of 1971, A UVF bomb kills 15 people on December 4 in Belfast.

In the four months leading up to internment, eight people died; in the succeeding four months, 114 were killed.

Bloody Sunday

Thirteen people died on Bloody Sunday

Thirteen Catholics are shot dead by members of the Parachute Regiment at a civil rights march in Derry on January 30, 1972. The soldiers say they were fired upon first; Catholics say the soldiers ran amok, shooting many in the back as they fled.

On February 2, the British embassy in Dublin is burned down. And 20 days later, the Official IRA bombs the Parachute Regiment's barracks in Aldershot, killing seven civilians.

Direct Rule After further bombings, Faulkner is summoned to London in March to be told by British Prime Minister that London is taking control of security.