Tonight’s seminal interview with Ian Paisley brings to an end any pretence that Ian Paisley and Peter Robinson like each other.
The brutality and clarity with which Dr Paisley speaks demonstrates the strength of feeling behind his words.
Perhaps in several years, when safely out of office, Mr Robinson will respond in kind.
Unlike last week’s instalment of Eamonn Mallie’s interview with Dr Paisley when the former First Minister’s memory was often absent and his words halting, tonight’s savage defenestration of the man who was at his side for the vast bulk of his long political career is delivered with venomous, if elderly, strength.
Dr Paisley appears to recall events firmly, almost as though he has been waiting for six years to say this publicly.
Journalists who knew something of what had gone on during Dr Paisley’s departure from office (though few, if any, knew several key details revealed tonight) have long wondered why he took so long to speak out.
If he wanted to secure his son’s position in the party, that was assured the night he trounced Jim Allister in North Antrim almost four years ago.
Perhaps the illness which almost took his life in early 2012 was a factor; it was just months after getting out of hospital that Mr Mallie began filming at the Paisley home.
Whatever the motivation, this devastating intervention cannot benefit the DUP.
The party will hope that Dr Paisley’s extraordinary departure from the rules he laid down for others, principally that party and church dirty linen should be washed indoors, will dramatically lessen the impact. There is no doubt that some former colleagues will now view their former leader with little more than contempt, given what he has done.
But for the ultra-loyal Paisleyites, this intervention is likely to be a bitter blow.
Some will have hoped that the suggestion that their political hero was put under pressure to quit was wrong; now they have it from the horse’s mouth.
Though most if not all of the DUP’s MLAs probably agreed by spring 2008 that it was time for Paisley to go, this astonishing spat will re-open fissures between those instinctively loyal to Paisley and the Old DUP and those allied to Robinson’s New DUP.
With double elections just five months away, even in the absence of a serious UUP or TUV challenge, such internal strife can only be unsettling.
Peter Robinson has experience of life at the centre of a political storm and has ferocious survival skills.
However, publicly at war with the party’s founder and with his son as one of its eight MPs, the DUP leadership is in utterly uncharted territory.