As IRA violence continued, Secretary of State William Whitelaw turned to the political leaders for a way forward. In March 1973 London proposed an 80-member assembly - with unionist and nationalist representation - to take over the affairs of state.
Elections were held and the power-sharing executive established. But the vote revealed deep divisions amongst unionists. That division deepened at a meeting in December called at Sunningdale to discuss Irish government involvement in the future affairs of Northern Ireland.
After three days of negotiations at the civil service college at Sunningdale, Berkshire, all of the parties signed an uneasy agreement establishing a Council of Ireland and a linked advisory assembly.
The unionists, led by Brian Faulkner, saw the council as nothing more than an advisory body which would improve cross-border economic development. The nationalist SDLP envisioned it as the foundations of eventual re-unification with the Republic.
But hardliners such as the Democratic Unionists' Ian Paisley, saw the deal as a sell-out. The majority of Ulster Unionists agreed and the loss of their support unseated Brian Faulkner.
At the same time, the Ulster Workers' Council organised a massive strike to destroy the deal. The UWC, headed by senior unionist/loyalist figures including Ian Paisley and William Craig of Ulster Vanguard, co-ordinated action which cut power and the supply of goods.
Loyalist paramilitaries became involved in enforcing blockades and eventually UUP members of the power-sharing body resigned.
The institutions collapsed and London imposed direct rule - an arrangement that would remain in place for 26 years. The political vacuum was once more filled by violence.
