Reverend Ian Paisley, who led the DUP for 37 years

Former DUP leader Ian Paisley has said it was a "mistake" to invite Pope Benedict XVI to Britain.

The Pope's trip in September will be the first official state visit by a Pontiff to the U.K. and the first papal visit since John Paul II in 1982.

But Paisley was adamant: "I think he should not be invited to the country." For over five decades Paisley has a history of denouncing the Catholic Church.

"We have had a terrible happening in Ireland with the priests and monks and nuns all taking part in acts of disgraceful behavior with young people, and we haven't seen the Catholic Church taking a strong stand on this," he told the BBC World Service.

He added: "A person, like some of the priests we've had, destroying the lives of young people and then going out and saying 'I can forgive sins', it's only right that be called what it is. That is anti-Christ in teaching and in doctrine."

Pasiley stated he believed firmly the pope was the anti-Christ.

“Well it’s quite true. [The pope] does seek by his claims to replace Christ. And he puts himself in the place of Christ.

“Take the list of names that he calls himself. The Roman Catholic Church turns to us and says you shouldn't call him the anti-Christ. Well, if a man comes to me and says he can forgive sins, then he is taking the place of Christ – no one can forgive sins except God.

“A person like some of the priests we’ve had destroying the lives of young people and then going out and saying I can forgive sins – it’s only right that be called what it is. That is anti-Christ in teaching and in doctrine.”

He also stood by claims that Catholics were vermin who bred like rabbits, he said: “I don’t think that it’s wrong to say that the Roman Catholic Church did believe that they [adherents] should have very large families. And large Roman Catholic families were brought into existence simply because of that.”

Asked whether he regretted such comments, he said simply: “I haven’t said anything that is contrary to what I believe to be truth. And for me to say that I am going to turn my back on all I’ve said would be nonsense. I believed it and I said it, and it stands the test."

The 84-year-old former Northern Ireland first minister said arrangements for the Pope's UK visit had been made in "secret."

"Nobody knows who made the thing; you go and ask a question of any minister and he says he doesn't want to have anything to do with it," he said.

The Pope's itinerary includes a reception with the Queen at Holyrood House in Edinburgh and open-air Masses in Glasgow, Birmingham and London. He will also attend a celebration of Catholic education and a meeting with the Archbishop of Canterbury in London.