Recent comments by Mr David Trimble, the Ulster Unionist Party leader, criticising the Republic of Ireland show he has "still much to learn", the Labour Party leader, Mr Rabbitte, has declared.
Speaking to the Chicago Sun-Times newspaper last week, Mr Trimble said the Republic would not have "a reason to exist were it not for its Catholicism and anti-Britishness".
This was the second time "within a matter of months" that the UUP leader had made "ill-considered and ill-informed comments about his neighbours south of the Border", said Mr Rabbitte.
"Nobody would deny that the Republic has its serious problems or that we have our share of zealots, but few people would recognise the picture of this State painted by Mr Trimble," Mr Rabbitte said.
"Ironically, Mr Trimble's comments are actually likely to play in to the hands of the small minority who do espouse the sort of crude anti-Britishness that Mr Trimble claims to decry," the Labour leader added.
