UK stem-cell researchers face the prospect of greater international isolation as opponents in the European Parliament and the United Nations consider moves to restrict their work.
A bid to get therapeutic cloning for research purposes outlawed was to have been put to the UN general assembly on Monday, although this would not have been binding for the UK government.
A deal struck between countries opposed to experimenting on cloned human embryo cells, which include the US and some Latin American and European Catholic nations will delay discussions on the matter for a year.
More significant are amendments to the European Union tissues directive, which are thought to include bans on the use of embryonic stem cells and stem cells from cloned embryos.
The directive will receive its second reading next week.
A source within the Department of Health said that such ethical considerations should not be included in the discussion yet and could lead to the collapse of the whole directive, which aims to regulate the quality of tissue for transplantation.
But he admitted that if the amendments gained support from 314 MEPs, the commission would be forced to consider a ban that he felt was unacceptable.
Austin Smith, Medical Research Council research professor of stem-cell biology at Edinburgh University, said he hoped the UK would stick to its pro-research position. "It is wrong to ban research that is not harmful and that potentially could have great benefits," he said.
Professor Smith said the UK's stance on the issue was making it an attractive place for researchers. He said he had been inundated with applications from foreign postdoctorates who wanted to pursue stem-cell research.
Roger Pedersen, professor of regenerative medicine and director of the Centre for Stem Cell Biology and Medicine at Cambridge University, said the attack on embryo research was part of a concerted strategy that aimed to outlaw abortion worldwide.