Dr David Muir, Director of Public Policy at the Evangelical Alliance, said: "I would like to thank Gordon Brown for recognising the crucial relationship between ethics and science in this important debate by allowing a free vote.
"We now hope MPs will use their votes wisely to further the needs of patients, rather than merely to further the interests of some scientists."
Dr Justin Thacker, Head of Theology at the Alliance and a medical doctor, said: "Years of embryonic research to date have produced very few tangible benefits for those suffering from the relevant medical conditions.
"In contrast, adult stem cell research has shown significant promise without the ethical complications.
"It's remarkable that those who claim to put the patient first have placed so much emphasis on legalising further embryonic research, which at present can hardly be justified."
Church of England clergy also waded into the row over a free vote earlier in the week. The Bishop of Lichfield, the Rt Rev Jonathan Gledhill, called the Bill immoral and stressed that "no one party has a monopoly on morality". The Free Church of Scotland's magazine, meanwhile, carried a major article by Dr Calum MacKellar of the Scottish Council on Human Bioethics in which he called Britain a "rogue state" for potentially heading down the "dangerous new road" of research into animal-human embryos.
Dan Boucher, Director of Parliamentary Affairs for Care, said that he welcomed the Prime Minister's commitments if they genuinely meant MPs would be free to vote in any direction according to their conscience.
"Contrary to some media reports over the weekend the Human Fertilisation and Embryology Bill is not only a matter of concern for Catholics, it is also a matter of very serious concern for many Protestants, including most evangelicals," he said.
Scientists say the Bill would keep Britain at the forefront of embryo research and overcome the present shortage of embryos needed to make stem cells for research into cures for a range of illnesses, including cancer and Alzheimer's disease.
