By Michelle Roberts
BBC News health reporter
The government has had a proven track record for supporting scientists in their quest to find new ways to cure debilitating diseases.
Hybrids are made using an animal egg mixed with human genes
Unlike the US, it gave a resounding "yes" to requests to do stem cell work, and has given the thumbs up for researchers to do therapeutic cloning.
But its latest plan to ban experts from making hybrid embryos has caused an uproar in the scientific community.
It is generally agreed that laws set out in the 16-year-old Human Fertilisation and Embryology Act need updating because science has moved on significantly.
Also, experts accept that a balance needs to be struck between pioneering science and the moral and ethical ramifications of allowing experimental work.
But leading UK scientists argue the decision to ban hybrid embryos - albeit a temporary ban - is a "short-sighted, knee-jerk reaction" to public concerns voiced during a consultation on the new White Paper.
One of the scientists applying to do hybrid work, Dr Stephen Minger of Kings College London, said: "I am confused as to how the government has come to this position."
The Department of Health ran a consultation on the overhauling the Human Fertilisation and Embryology Act and received 535 responses.
These included scientists, medical bodies, patient representatives, ethicists and faith communities.
About 340 of 535 responses to the consultation addressed the issue of hybrids.
The broad picture was of widespread opposition to allowing such creations, with over 80% of the responses on this point opposed.
However, concerns have been expressed that organised groups, opposed to any kind of embryo research, made up the bulk of respondents.
Dr Evan Harris MP, Liberal Democrat member of the Science and Technology Select Committee, said: "I would be disappointed that the government has said it would ban this research on the basis of not even an opinion poll but maybe 50 people who wrote in after a consultation.
"There were only 500 odd responses altogether and there were 30 odd questions and this was one question, two paragraphs.
"The general view in this country has been that we should allow research within strict limits that gives the chance of finding causes of disease and potential new therapies."
He acknowledged that people were queasy about the idea of mixing humans with animals, but added: "Queasiness is not a good reason to prevent research going ahead that is strictly regulated."
Professor Chris Shaw, another of the scientists applying to do hybrid work, also from Kings College London, agreed: "The same reservations were held when people talked about using any animal product. We still use heart valves from pigs to treat people with heart valve problems.
"They had this consultancy process and a lot of the very active and well-funded lobbying groups were very effective in this in getting their views across and their concerns."
The scientists argue the true picture was skewed because supporters of their work submitted a joint statement to the consultation process, while opponents submitted their objections independently.
Professor Shaw added: "While we understand their concerns, we think they are largely founded on misinformation.
"People think we are generating a hybrid animal. This is just cells, just for science. No animal is ever going to be created."
Josephine Quintavalle from CORE ethics disagrees. She believes the government is finally listening to widely-held public concerns, not bowing to select public pressure.
She said: "We have moved into an era when we are starting to realise we have made some very big mistakes in terms of the environment and our attitudes to the natural world. It is the same kind of mindset.
"You can't polarise everyone that is opposed to human cloning as being religious zealots. There is a very strong scientific community worldwide that is concerned about responsible genetics."
She agreed that opinion polls could be biased, but said it was an absurdity to suggest the government had taken the decision purely on the basis of its own consultation.
"I would like to credit the government with slightly bigger vision than that. I think they have given it really proper consideration."
She said the public had always been divided on contentious scientific issues, including stem cells and therapeutic cloning.
"Historically there was a split vote on most of these issues. There was opposition from many different sectors of society, but the public voice just wasn't up to it and things got rushed through parliament very quickly."
She said it was easier to make a case against the science when it involved mixing humans with animals.
"There's the yuk factor. There is an innate repugnance that we would mix the species in this way."
A spokesman from the Department of Health said: "Previous reviews in this area show on-going and widespread support for a ban on creating human-animal hybrids and chimeras for research purposes."
Health Minister Rosie Winterton said the proposals were "based on extensive public consultation", adding that the debate would continue in parliament.
Indeed, PM Tony Blair has stressed he is not dead set against the idea of hybrids.
He said: "If there's research that's going to help people then we want to see it go forward."
He said the existing law was going to be amended "to allow us to have some flexibility."
The legislation, which still has to be passed by parliament, includes a clause allowing for the possibility that this type of work should be permitted in the future.
When Public Health Minister Caroline Flint announced the changes she explained: "We have been guided by the science that is already there but also future developments...we are also minded by the moral compass of how those technologies are used."
She said the hybrid debate was "a good example of where developments have moved on but we are not in a place where we can say 'yes we can do this now'."