(File photo) A veterinary worker takes samples from a hen in the Danube Delta village of Murighiol.

London - Leading scientists last night condemned the decision by flu researchers to continue their controversial research into the deadly H5N1 bird-flu virus, which has already created a mutated strain that can spread between mammals - including humans.

Forty of the world's most prominent flu researchers have decided to lift their voluntary moratorium on studies into the airborne transmission of the strain, which they imposed upon themselves last January following public outrage over the work.

They say that the benefits of the research in preventing and dealing with a future flu pandemic outweigh the risks of an accidental leak of the mutant virus from a laboratory, or the deliberate attempt to create deadly strains of flu by terrorists or rogue governments.

However, other leading scientists have vehemently denounced the decision. Professor Lord May, a former government chief scientist and past president of the Royal Society, said there are two possible downsides to research that deliberately aims at making the H5N1 bird-flu virus more infectious to humans.

“As this research becomes more widely known and disseminated, there is the opportunity for evil people to pervert it,” Lord May told The Independent. “My other concern is the statistics of containment are not what they ought to be.

“The dangers of going ahead with the research outweigh the benefits of what may emerge. As I look at it, on the balance of probabilities, going ahead and lifting the moratorium is more dangerous than not going ahead.”

Sir Richard Roberts, who won the Nobel Prize in medicine in 1993 and is an expert in genetic engineering, said there has not been enough public consultation about the work. “The decision to lift the moratorium, which seems to have been made by a small group of self-interested scientists, makes a mockery of the concept of informed consent,” Sir Richard said.

He asked: “Should we be trying to engineer in the laboratory a virus so dangerous that accidental release could wipe out a significant portion of humanity? I vote no.”

The ending of the voluntary moratorium was announced last night in the form of a letter signed by 40 flu scientists to the journals Science and Nature, which published the original H5N1 transmissions studies by Ron Fouchier of the Erasmus Medical Centre in Rotterdam and Yoshihiro Kawaoka of the University of Wisconsin-Madison.

The scientists independently discovered that they could mutate the H5N1 strain of bird-flu so that it could be transmitted through the air between laboratory ferrets, the standard animal model used to study influenza in humans.

Scientists fear that if airborne transmission became possible it would lead to a deadly flu pandemic killing millions of people, because most of the individuals who are known to have been infected with H5N1 die from the virus.

Dr Fouchier said: “We really need to understand how these viruses become airborne.” Dr Kawaoka added: “We want the world to be better prepared than we are. We understand the risk and consider the H5N1 research safe. There can never be zero risk, but the risk can be managed and we believe the benefits of H5N1 research outweigh the risks.”

However, other virus experts disagreed. Simon Wain-Hobson, professor of virology at the Pasteur Institute in Paris, said: “There has been no consultation with any virologist outside the flu community on this and I'm not convinced of the benefits of this research. The risks are clear for all to see. Civil scientists are not here to increase the risk from microbes. We can't make the microbial world more dangerous.” - The Independent