O'Brien compared abortion to the 1996 Dunblane massacre, in a sermon marking the anniversary of the 1967 Abortion Act, The London Telegraph said Thursday.
He said pro-choice politicians could not expect to remain full members of the Catholic Church, and implied that abortion is a worse tragedy than the murder of 16 children in a Scottish school, the newspaper said.
"We are killing -- in our country -- the equivalent of a classroom of kids every single day," he said. "Can you imagine that? Two Dunblane massacres a day in our country going on and on. And when's it going to stop?"
The sermon was delivered at St. Mary's Cathedral in Edinburgh.