The Ulster Workers' Council strike of 1974 crippled Northern Ireland as loyalists took to the streets to bring down a new power-sharing government.
Forty years on, politicians and academics speak to Brendan Hughes about its significance and the continuing impact on Stormont today
One of the defining events of the Troubles, the legacy of the Ulster Workers' Council strike still reverberates 40 years on.
Over the course of two weeks protesting loyalists and unionists reduced the north to a standstill and brought down a new power-sharing executive.
Roads were blocked with barricades and hijacked vehicles, while electricity supplies were disrupted as staff walked out of their workplaces.
Farmers were forced to dump uncollected or unprocessed milk and fresh food failed to reach shops.
There were problems maintaining petrol distribution and a lack of electricity meant pumps did not operate for periods throughout much of each day.
A state of emergency was called by then secretary of state Merlyn Rees as the strike deepened and the economy was crippled.
The strike was called in protest at the December 1973 Sunningdale Agreement which established a power-sharing government with nationalists and provisions for a Council of Ireland.
Unionists feared the proposed body - which promoted coordination between northern Ireland, the Republic and UK governments - would lead to a united Ireland.
The Ulster Workers' Council (UWC) strike began on May 15 1974, the day after a motion condemning power-sharing and the Council of Ireland was defeated by 44 votes to 28 in a new assembly elected the previous year.
Critics say many were intimidated into joining the strike due to the involvement of loyalist paramilitary groups, although loyalists said they merely helped mobilise support.
On the first day only 10 per cent of workers joined the strike despite unionist politicians calling for action.
But during the two-week action, loyalist paramilitaries killed 39 civilians, including the 33 victims of the Dublin and Monaghan bombings.
Austin Currie, who was an SDLP minister in the power-sharing executive when the strike started, said paramilitary intimidation was a huge problem.
"People weren't allowed to go to work. The Protestant paramilitaries set up road blocks and intimidated people," he said.
The strike gained support as severe disruption across the north continued.
"The British government, which had control of security, didn't take the necessary forceful action to deal with the intimidation," Mr Currie said.
"I have always believed that if effective action had been taken in the early days of the strike to stop intimidation and keep the roads open, the strike would have fizzled out.
"But when that didn't happen the confidence of the strikers increased and disillusionment among ordinary people increased."
Political commentator and academic David McCann agreed that loyalist paramilitaries played an important part in the strike.
"A lot of unionists may not have liked a lot of the violent aspects of it but they were fearful of the Council of Ireland," he said.
"People did genuinely believe that this would lead them into a united Ireland.
"The paramilitaries were essential for making the strike successful in terms of blocking the roads and making people not go to work."
On day 14 the crisis came to a head when UUP leader Brian Faulkner resigned as chief executive of the power-sharing government, effectively ending the project and causing the collapse of the Sunningdale Agreement.
The next day work began again across the north as the UWC leaders officially called off the strike.
It took until 1998 before Sunning-dale was succeeded by another cross-community political settlement, the Good Friday Agreement.
It was memorably described by former SDLP deputy leader Seamus Mallon as "Sunningdale for slow learners".
Mr Currie (74), who now lives in Kildare, described the collapse of the executive following the UWC strike as a "terrible tragedy" that is still having repercussions at Stormont today.
"The same essential parts of Sunningdale became the good parts of the Good Friday Agreement," he said.
"The tragedy was that it took nearly 30 years for the lessons of Sunningdale to be learned by the same people and it took the loss of another 2,500 lives and the creation of a political divisiveness that we are still grappling with.
"The collapse of Sunningdale was a terrible tragedy for which both loyalists and the IRA have almost equal responsibility."
Dr McCann, who holds a PhD in north-south relations, said the strike was a significant moment for unionism. However, he said the signing of the Good Friday Agreement shows that the strike action largely "delayed the inevitable".
"This was their big moment where they actually changed the course of government policy, and that you had a period of 'Ulsterisation'," he said.
"In its wider legacy it just delayed the inevitable because in 1998 you essentially got the Sunningdale Agreement."
* ACTION: Over the course of the Ulster Workers' Council strike of 1974 roads were blocked with barricades and hijacked vehicles, while electricity supplies were disrupted as staff walked out of their workplaces