The DUP's Ian Paisley and Peter Robinson during an election campaign in the 1970s.
THE BBC TV prog-ramme on the Rev Ian Paisley is the supreme example of the saying that revenge is a dish best served cold, for he has long been waiting to exact vengeance on The North's First Minister Peter Robinson.
He was clearly scalded by the fact that Mr Robinson and other senior party members concluded, in 2008, that the time of Mr Paisley's departure had arrived.
But he has waited for years before exposing the depth of his personal bitterness.
In the programme, Mr Paisley and his wife Eileen maintain a scathing stream of accusations against his one-time DUP deputy: they allege disgraceful behaviour, dirty tricks and dirty deeds, even of political assassination.
The irony is that Mr Paisley has himself always been blamed for a series of political assassinations of opponents, particularly of Ulster Unionist leaders ranging from Terence O'Neill to David Trimble.
Extravagant and vitriolic language has always been a feature of Paisleyism, but never before has it been directed against former colleagues rather than enemies.
He is fond of quipping that he has a particularly tough hide, but the events of 2008 touched him to the quick and demonstrated that his legendary armour was capable of being pierced.
He was ever notorious for his bluntness, as when he revealed on the programme that when Tony Blair told him he was converting to Catholicism his harsh response was: "You're a fool."
In 2008 he was top of the world having -- with Peter Robinson's sharp tactical brain -- built up his party into Northern Ireland's largest and then using that strength to do the deal with Sinn Fein and become first minister.
Although there was some hardline grassroots grumbling about this, it was drowned out by astonishment and near-universal delight that after decades of conflict the old warhorse had opted for powersharing.
This ushered in a new era both for himself and for the North as a whole. He was feted around the world, forging new relationships with figures such as Bertie Ahern. He basked in his new role.
Once in office he left actual administration to others and did not bother himself with detail, instead treating his new role as a protracted and hugely enjoyable lap of honour.
He remained head of the party and the church he had headed for half a century.
Although he was in his 80s, and had lost some of his earlier sharpness, he and his ultra-loyal family appeared to assume that he would go on indefinitely, like some figure from the Old Testament. But resentment in his party and his church grew -- almost all of it behind closed doors, for both have a tradition of omerta and not washing dirty linen in public.
Fundamentalists within his church were uneasy about the suddenness of his change of heart, and about their moderator's very public friendship with Martin McGuinness.
His slogan had been "Smash Sinn Fein", but now the two were chuckling away.
Within his party there was also an undercurrent among some figures of unease about the whole idea of being in government with republicans.
Elsewhere in the party there was also political and personal ambition. Some lieutenants felt his departure could free up senior jobs for them; some also felt it would open the way to a more modern and less religious image which could help hoover up voters from rival unionist parties.
Such factors combined to mean that within months Mr Paisley had lost all three of the posts he treasured: he was given a seat in the House of Lords, as Lord Bannside, but this was scant consolation.
As someone who had always been patriarch of both party and church, his position had never been seriously challenged in either, so that he had long complacently regarded both as essentially family concerns.
One of his sons is a Westminster MP while another is a minister in his church.
It has often been said that he had to be number one in any organisation he was involved in, and the thought that he would completely lose all power in government, party and church was frankly unimaginable for him.
His triple demotion cut him to the quick and he has clearly been nursing a deep sense of grievance, in particular against Peter Robinson, his long-time deputy whom he never thought would displace him.
Like Margaret Thatcher, he has been unable to see his departure in terms of generational renewal, instead regarding it as betrayal. In 2008 he went quietly, but since then he has clearly been biding his time for personal vengeance.
The sense of the personal is to the fore here, for the attacks of himself and his wife are relentless.
The fact that they are almost bound to inflict damage on the church and the party shows no sign of troubling him.