For more than three decades, the Democratic Unionist Party, now poised to be Theresa May’s “little helper” in government was a party of protest for many unionists and Protestants in Northern Ireland.

Reverend Ian Paisley shocked the community in the North in 1970 when he was elected to Westminster under the banner of “Protestant Unionist”.

The party was relaunched as the Democratic Unionist Party a year later, motivated by a resistance to any influence of the Irish government in the affairs of Northern Ireland. Thousands of the people who became members of the party shared Paisley’s contempt for the institutions of the Catholic Church.

The DUP was the outsider party which mercilessly challenged the establishment, but one that not infrequently, too, played at being would-be armies, while always pushing the boundaries of lawfulness.

Angry crowds at Ballybay District Court, Co Monaghan in 1986 over the “Clontibret Affair”, the 1986 incursion by loyalists led by Peter Robinson in the the Republic. Photograph: Peter Thursfield/The Irish Times. No one was safe from the rapier rhetoric of Paisley, who besides being leader of the DUP was also the Moderator of the Free Presbyterian Church, which was also his own creation. He was a combination of a bellowing 17th Century preacher and a firebrand political orator. Neither of his successors Peter Robinson nor Arlene Foster managed to emulate his stentorian traits.

Mr Paisley was chucked out of practically every political edifice in which he ever served including Westminster, Stormont and the European Parliament where he caused a rumpus during a visit by Pope John Paul.

He regularly excoriated British prime ministers, detesting the likes of Ted Heath whom he alleged would have been delighted “to have towed Northern Ireland out into the Irish Sea and let it sink to the bottom.”

She is opposed to same sex marriage and heads a party predominantly anti-gay and pro-Brexit. Not even members of the Royal family escaped his wrath; in 1958 he denounced the Queen Mother and Princess Margaret for “committing spiritual fornication with the anti-Christ” by visiting Pope John XXIII.

In 1963, after John XXIII’s death, he expressed his satisfaction that “this Romish man of sin is now in Hell”.

“I am anti-Roman Catholic,” he told his supporters, “but God being my judge, I love the poor dupes who are ground down under that system.”

While Mr Paisley condemned Loyalist paramilitary attacks on Catholics throughout his career, in the 1980s he flirted with the prospect of Protestant “people’s militias” and he once conveyed myself and a number of other journalists to a hillside in Co Antrim at night to witness 500 men in military formation brandishing firearms licences.

A serial protester, Mr Paisley and his party helped to bring Northern Ireland to its knees in 1974 during a workers’ power strike which made the North close to ungovernable in opposition to a power sharing executive, involving catholic members of the Social Democratic and Labour Party headed by Gerry Fitt and moderate Unionists like Brian Faulkner.

Mr Paisley was dubbed a wrecker by several prime ministers and various secretaries of state in NI.

Repeated efforts of British governments working hand in glove with the Irish government to try and end the Irish Republican Army’s campaign of violence served only to fuel the DUP’s relevance in opposing Dublin interference in Northern Ireland.

The arrival of the so called ‘Iron Lady’ Margaret Thatcher in winter 1985 in Northern Ireland resulted in effigies of Mrs Thatcher being set alight at a bumper rally against the Anglo Irish Agreement signed by Taoiseach Garret FitzGerald and Mrs Thatcher.

Parallel to the growth of the DUP politically and its growing aggression on the streets, Sinn Féin under the leadership of Gerry Adams and Martin McGuinness dramatically expanded politically despite an escalation in the IRA’s violent campaign boosted by a shipment of Libyan weapons and Semtex.

First Minister Ian Paisley and Deputy First Minister Martin McGuinness, both now deceased, after being sworn in as ministers of the Northern Ireland Assembley in 2007. Photograph: Paul Faith/PA Further political efforts to end the rival sectarian violence resulted in the signing of the Good Friday Agreement which ultimately led to an end to the IRA’s campaign of violence and the agreement by the leading Ulster Unionist party headed by David Trimble to enter a power sharing government with republicans for the first time.

The DUP refused to entertain Sinn Féin in government without getting rid of their arsenals.

Following confirmation by catholic priest Fr Alec Reid that he had witnessed the IRA “putting their arms beyond use” Ian Paisley led his party into government with Sinn Féin. Some called this a “road to Damascus Conversion” by Paisley but he told me in his last interview before expiring that ultimately he had to accept the “will of the people” once his former republican enemies had put away their guns and accepted the police and the rule of law.

Paisley paid the ultimate price however within his Free Presbyterian Church for going into government with Sinn Féin and was pushed out of the pulpit of his own Martyrs Memorial Church. Finally his former political colleagues forced him to surrender the leadership of the DUP because he was seen to be too comfortable in the company of his Sinn Féin deputy leader and former IRA commander Martin McGuinness.

His deputy Peter Robinson took over from Mr Paisley. He too ended up in the firing line over a number of liberal gestures and found his position untenable.

The current DUP leader and now the lifeline to the survival of Theresa May, Arlene Foster, was Mr Robinson’s choice of replacement when he left the political stage. She has remained well to the right in both matters of politics and questions of morality. She is opposed to same sex marriage and heads a party predominantly anti-gay and pro-Brexit.