The leader of Scotland's Catholic Church has launched a scathing attack on Gordon Brown over "monstrous" plans for embryo research.
Cardinal Keith O'Brien will use his Easter Sunday sermon to criticise the controversial proposals to allow scientists to create human-animal embryos for research.
Supporters of the Human Fertilisation and Embryology Bill believe such hybrid embryos could lead to cures for diseases including multiple sclerosis and Alzheimer's disease.
But in his sermon, Cardinal O'Brien will condemn Mr Brown for imposing a three-line whip on Labour MPs over the issue, not allowing them a free vote.
He will also claim that the Bill would lead to the endorsement of experiments of "Frankenstein proportion".
In his sermon, which was released in advance, the Cardinal says: "This Bill represents a monstrous attack on human rights, human dignity and human life.
"In some European countries one could be jailed for doing what we intend to make legal.
"I can say that the Government has no mandate for these changes: they were not in any election manifesto, nor do they enjoy widespread public support."
He adds: "One might say that in our country we are about to have a public Government endorsement of experiments of Frankenstein proportion - without many people really being aware of what is going on."
In the Easter message, the Cardinal describes the practice as "grotesque" and "hideous".
