The Reverend Ian Paisley has done himself no favors with his harsh attacks on former party colleagues in a BBC interview.

Paisley left the political arena in 2008 trailing clouds of glory after agreeing to share power with Sinn Fein Deputy First Minister Martin McGuinness in a move that transformed Northern Ireland.

The journey from Protestant bigot to far-seeing political leader was a long one, and Paisley deservedly was hailed as an extraordinary figure after making that move.

In power, he and McGuinness cemented a relationship that ensured the peace process would bed down roots and establish itself for the long run.

After a graceful retirement at 82, Paisley looked likely to enter the pantheon of Northern Irish leaders who made a profound difference during their lives.

However, Paisley has now besmirched his own reputation with a vicious attack on his successor, First Minister Peter Robinson, who to his credit has refused to respond to Paisley’s rage.

That there was tension between Paisley and Robinson was well-known. But the extent and the evident hatred between them comes as a surprise.

Paisley had a very long innings, and his retirement was a graceful exit for a man who had been on the Northern Ireland stage for well over a half century.

It was Robinson’s turn, and Paisley of all people, having deposed several Unionist leaders, should have been aware of that.

However, it appears that the bad blood ran very deep. Paisley used very intemperate language to assail his successor.

There is no question that Paisley will still go down in history as one of the most unlikely political transformations ever.

But it is also clear from his final interview that he retains a vicious edge and a long memory when it comes to those who he believes have crossed him.

Quite why he and his wife Eileen made such biting allegations at this stage of their lives is unclear.

But during the interview, we saw a lot of the old Paisley and the nastiness he brought to the stage.

This is the man who mounted an incredible attack on Pope John Paul II during his appearance in the European Parliament.

This is the man who, while he now denies it, incited thousands of young Protestants to take to violence against their Catholic counterparts.

This is the man who used the most horrific language imaginable when speaking about Catholics and their faith, and who also in his latest interview said he would never have allowed one of his children to date a Catholic.

It is a pity that we are forced to recall this Paisley, and not the good man who realized it was time to make peace and end the civil conflict in Northern Ireland.

As he nears the end of his long life, Paisley can surely reflect on the remarkable journey that took him from Protestant preacher so extreme that he was shunned by many, to First Minister of Northern Ireland.

His story should be an example, like that of F.W. de Klerk in South Africa, of how a human being can change no matter how extreme their views are to begin with.

Paisley should have passed quietly from the scene, enjoyed his retirement and the kudos he richly deserved.

Instead the old Paisley has reared his head with a ferocity and anger aimed at his own colleagues.  It is to their credit that they have not responded in kind.