The DUP leader, Ian Paisley, has launched a strong attack on Pope Benedict XVI as he prepares to speak to a rally of the Independent Orange Order in Ballymoney, Co Antrim.
Mr Paisley is accusing the Pope of excommunicating every non-Catholic Christian and said Rome has not changed from its devilish ways.
Mr Paisley, the founder and head of the fundamentalist Free Presbyterian Church, said Pope Benedict had celebrated the July 12 by un-churching every denomination in Christendom excepting his own.
He had, said Mr Paisley, declared the Church of Rome alone was sole true church and all others were "not Churches in the proper sense of the word" but merely religious associations.
He said Rome had not changed and will never change and all Protestant churches must uphold that Christ is the head of the church, not the Pope.
The gospel message must go forth with trumpet blast, he said and all other messages were lying falsehoods and devilish deceptions.