SCIENTISTS have developed a pioneering new drug which they believe has the potential to protect against any strain of flu.
It is hoped the breakthrough treatment, which would be administered by inhaler or as a nasal spray, would guard against current, future and even pandemic strains of the virus.
The research project was led by Professor Garry Taylor and Dr Helen Connaris at St Andrew's University in Fife.
It emerged a week after doubts were raised about the effectiveness of Tamiflu - the anti-viral drug stockpiled by the UK government.
Researchers said Tamiflu was no better than paracetamol in relieving symptoms and could not stop the disease spreading nor prevent people developing complications.
Professor Taylor, Professor of Molecular Biophysics, said: "We believe our approach has the potential to be used as a preventative against any current and new virus that emerges, such as H5N1, H7N9 and the very recent H10N8."
Unlike Tamiflu which attacks the flu virus, the new drug targets the way the virus enters the body.
To do this, the Scots team created a protein which prevented the flu virus from binding to sugar molecules lining the respiratory tract and passing into cells.
The drug was tested in mice by scientists at the Roslin Institute in Edinburgh and at St Jude Children's Research Hospital in Memphis, in the United States.
The studies showed that a single nasal dose completely protected mice even when given seven days before a potentially lethal challenge with the pandemic 2009 H1N1 virus.
As well as surviving, the mice developed antibodies against the virus suggesting they were "vaccinated" against any future exposure to the virus.
Further tests will now be carried out, before the drug is put forward for clinical trials.
Influenza remains a constant global health threat with annual epidemics claiming up to 500,000 lives each year according to the World Health Organisation.
The emergence of new strains from birds in recent years has revealed the ability of the virus to cross species barriers and to pose pandemic health threats.
While vaccines are the cornerstone of prevention, these are not always effective and take time to develop in quantities needed to treat whole populations.
Dr Robert Webster, Rose Marie Thomas Chair of Virology at St Jude, one of the world's foremost experts on influenza, was one of the researchers involved in the project.
He said: "The work is exciting and potentially of great importance in this era of emerging viruses such as H7N9 that have pandemic potential."
The research paper entitled "Prevention of influenza by targeting host receptors using engineered proteins" is being published in the Proceedings of the National Academy of Sciences of the USA (PNAS) this month.
Last week's report by The Cochrane Collaboration, a not-for-profit organisation which carries out reviews of health data, was written after a five-year battle to see the full results of all trials of Tamiflu.
Roche, which makes the drug, said that the researchers had failed to understand the data and had made "basic mistakes".
Other scientists said that it was too soon to conclude that the antiviral drug did not work, pointing to evidence suggesting that it saved lives during the 2009 swine flu pandemic.
The UK government has been stockpiling Tamiflu since 2006 at a cost of £473 million over fears about bird flu.
It is not widely prescribed for regular flu.