[7] From the start, there was intermittent feuding between McKee's men and his former comrades in the Official IRA, as they vied for control of nationalist areas.

Rioting broke out in the Ardoyne area of north Belfast after an Orange Order parade, and three Protestants were killed in gun battles between the Provisional IRA and loyalists.

[9] See Battle of St. Matthews The leadership of the Provisional IRA had always planned to broaden their activities from defensive operations to an offensive campaign aimed at removing British rule from Northern Ireland.

This deterioration was due to the British Army's heavy-handed treatment of Catholics and nationalists in their efforts to combat republican paramilitaries.

After this point, the Belfast Brigade's strategy shifted from 'defence' to 'retaliation' and in January 1971, they began seeking out and attacking British Army and Royal Ulster Constabulary (RUC) patrols.

[12] He was charged and convicted for possession of the weapon and imprisoned in Crumlin Road Gaol, and Joe Cahill took over as OC of the Belfast Brigade.

The following day, Joe Cahill held a press conference in a school in Ballymurphy and stated that the operation had been a failure.

In the Belfast Brigade's Second Battalion alone, for example, twenty IRA volunteers were killed in the twelve months after August 1971.

Seamus Twomey, commander of the Belfast Brigade, declared that the British had violated the truce and shortly afterwards, his men opened fire on the troops.

Sean MacStiofain, the IRA chief of staff, formally announced the end of the ceasefire that night, in response to events in Belfast.

[17] In addition to attacks on the Army, a central part of the Belfast Brigade's campaign was the bombing of commercial targets such as shops and businesses.

The British Army proceeded to build fortified posts in republican west Belfast, thus hampering the IRA's freedom of movement.

After this setback, Seamus Twomey, who had authorised the Bloody Friday operation, was replaced as Belfast Brigade commander by Gerry Adams, with Ivor Bell as his second-in-command.

[21] Moreover, the Belfast Brigade changed its tactics in an effort to avoid the heavy losses in killed and captured they had suffered up to that point.

Billy McKee, by that time commander of the Belfast Brigade, responded with retaliatory attacks on Protestant civilians.

One of the most notorious of these attacks came on 13 August 1975, when an IRA team led by Brendan McFarlane machine-gunned Bayardo's Bar on Belfast's Protestant Shankill Road, killing five people and injuring over 50.

His critics were even angrier with his orders, in mid-1975, to attack the remaining Official IRA units in Belfast, in an effort to wipe out that organisation.

The ensuing feud led to the deaths of 11 republican paramilitaries and a number of nationalist civilians; such as the head of the Falls Road taxi association, whose business was affiliated with the Provisionals.

In addition, it was claimed by McKee's critics, notably Gerry Adams and Danny Morrison, that discipline in the Belfast Brigade all but broke down in this period, leading some IRA volunteers to slip into criminality.

A grouping of young Belfast Provisionals, led by Gerry Adams and Ivor Bell, emerged from internment in 1976, determined to restructure the IRA.

Firstly, they ousted Billy McKee as OC of the Belfast Brigade, accusing him of demoralising and discrediting the IRA by allowing it to become involved in sectarian and intra-republican feuding.

During the mass protests arising out of the dispute, IRA members in Belfast were encouraged, as well as the usual sniping and assassination attacks, to lead the rioting against the RUC and British Army in nationalist areas.

According to Bishop and Mallie, "At the height of the Hunger Strike in 1981 ... the cell structure collapsed out onto the streets as the IRA, police and army engaged each other in rioting.".

"[25][26] In 1990, senior Sinn Féin and IRA figure Danny Morrison was arrested in a house in Belfast where an informer was being interrogated.

In 2005, Denis Donaldson, a former Belfast IRA man and senior Sinn Féin worker, was "outed" as an informer.

In 1988, three Belfast Brigade IRA members were killed in Gibraltar by the Special Air Service (SAS) while on a bombing mission.

Two Belfast Brigade volunteers from Ardoyne planted a bomb in a fish shop in the Shankill Road where the UDA's leadership had arranged to meet.

IRA actions were heavily restricted by the Army Council in Northern Ireland's major urban areas to avoid civilian casualties.