In the UK, an under-pressure Gordon Brown is facing growing calls for a free vote on controversial legislation for embryo research. The Human Fertilisation and Embryology Bill includes plans to create human hybrid embryos for research purposes. Experts say this would give scientists the large number of embryos needed to make stem cells.

They would then be used to further medical research, potentially easing the suffering of millions. But some say using human-animal embryos for experiments would be ethically unacceptable.

Several senior members of the clergy, including Roman Catholic Cardinal Cormac Murphy-O'Connor, used their Easter sermons to condemn the plans and call for a free vote.

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Health Secretary Alan Johnson played down reports of ministerial rebellion and a government compromise: "There is no Cabinet split. We will deal with this issue in the same way we deal with all sensitive legislative issues and the PM made it plain three or four weeks ago that we will not be forcing people to vote against their conscience."

The Conservatives and Liberal Democrats say they will allow a free vote for their deputies on the bill, which is viewed as a key piece of legislation on the government's agenda.

It is due to come before the lower House again sometime later this year.