Ian Paisley was to denounce Margaret Thatcher as "the Jezebel who sought to destroy Israel in a day", while the usually mild-mannered Jim Molyneaux spoke of stench and deceit. Enoch Powell rose to proclaim that Thatcher's actions would be penalised by a "fall into public contempt".
Contempt was displayed when the massive gathering of unionists outside Belfast City Hall heard the memorable "Never. Never. Never" bluster of Paisley.
There is no exact figure on how many turned up, but we could guess at somewhere around 100,000, watching golf balls fly through the air at the hapless RUC.
Less than a year later, the future first minister, Peter Robinson, led 500 marchers into the village of Clontibret in Co Monaghan to protest against the imposition of the agreement.
For this action, he was fined around £1,500 for unlawful assembly. The wise-headed Garret FitzGerald knew the agreement would not immediately shift politics in Northern Ireland, but would begin a new direction.
Margaret Thatcher, for her part, was to claim that she had been duped into signing, but, irrespective of that, once the process was set, it was to be done so in stone – she never wilted.
The then-15 unionist MPs resigned and stood in by-elections in 1986 to continue the anti-agreement stance. Although those who stood were virtually guaranteed re-election, the unionist electorate did not march in massed ranks to the ballot box to express their rage – an early sign that certain sections were drifting away from the impassioned, fervent and fiery maelstrom of local politics.
Peter Robinson's generous tone last week after Mrs Thatcher's death reminded me of SE Hinton's coming-of-age novel That Was Then, This Is Now.
Robinson spoke of her as a positive and transforming force that led to a better Britain, but that he had twice been excluded from Westminster for unparliamentary language against the Iron Lady.
In noting that he classified politicians as either time-servers or those of conviction, he firmly attached her to the latter.
In some sense, conflicting words – given previous actions. But, possibly, also a sense that to bend a little achieves a lot.
Arlene Foster also spoke of Thatcher's single-mindedness and colossal status and praised her for being an "unashamed" free-marketeer.
Not remembering that the actions of 'Monetarist Maggie' had done much to harm a Protestant working class which was dependent upon heavy industry and a traditional working way of life.
They – like the workers of Scotland, Wales and the north of England – remain hammered, alienated and excluded long after the Thatcher period.
Economic alienation is one of many reasons why the Protestant working classes merely dribbled on to the streets to join the flag protest. Mass rallies are a thing of the past in a society that went through violence and then experienced relative peace.
There is no easily-defined 'Catholic' or 'Protestant' community now, but more varied groups that sit on various ideological, economic and cultural planes.
No constants now in a society (of course, for Margaret Thatcher, no such thing existed) that has fractured even more beyond the orange and green.
The growth in mixed marriages, fewer voters, the rise of Northern Irishness and the experience and affluence of sharing are far removed from the chaos of 1985.
Irredentist ideas and feelings bubble and rise from time to time, but unionists simply wanted, or grew to accept, compromise.
There is no capacity now to kick-start a type of unionism that simply acclaims 'No', or 'Never' – it has been tried and gone nowhere.
The year 1985 was a defining moment, as it was the point of recognition that there was an alternative to violence, that Irish nationalism had to be recognised and that the will of the people could no longer subvert the sovereignty of two parliaments.
As we know, Thatcher's downfall was her initial 'strength'. There is always a point when the hounding, demanding and asserting of your will over others will simply earn one enemies.
When she pronounced "You turn if you want to", she did not realise that, when those around her did, she would fall into the political wilderness.
She was simply inflexible in what is always a changing world. The local political leaders of that time, whether unionist or republican, had themselves been 'Iron Men' and proponents of inflexible beliefs and ideas.
However, they understood more than Thatcher that positive change comes not from blunt actions, but through the understanding that compromise is not a weakness. In her own words, she opined that "disciplining yourself to do what you know is right and important, although difficult, is the high road to pride, self-esteem, and personal satisfaction".
The high road found in Northern Ireland has taken us far beyond such selfish principles.
For unionist leaders, they should remain minded that 1985 was a lesson in learning that Northern Ireland had and continues to become a very different place.
Respectful condolences are a reminder of how far the DUP and others, who were less commiserating, have been stretched since the dreariness of the Thatcher era.
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