Scientists have made the first step towards creating a vaccine against swine flu after isolating the bug and decoding its genetic sequence, it was announced.
It is hoped pharmaceutical companies will take delivery of a prototype vaccine in the coming weeks in order to begin manufacturing on a large scale.
However it is likely to take several more months before the vaccine has been tested, licensed and produced on a large enough scale for vaccinations of the public to begin.
There have been 34 cases of H1N1 swine flu in Britain, including 13 children, and all confirmed cases are making a good recovery.
Scientists at the Health Protection Agency have isolated samples of H1N1 from British patients meaning it can be compared to samples from Mexican and American patients to establish if the virus is changing as it spreads around the world.
This isolate will enable scientists to gather more information on the characteristics of the virus affecting humans in Europe and compare those with that in Mexico and the US.
The team have also decoded the genetic information of the British samples which means scientists can understand how it works and identify sections of the virus that can be turned into a vaccine.
Health Secretary Alan Johnson said: "A significant step towards protecting the world's health against swine flu has been taken.
"The speed with which vaccine prototypes can be created to combat potential pandemics is testimony to the dedication and world-class expertise of Health Protection Agency researchers.
"We have been preparing for the possibility of a pandemic for some time. We now look to the vaccine industry to produce the required quantities of vaccine as quickly as possible."
Professor Maria Zambon, Director of the Health Protection Agency's Centre for Infections, said: "We are continuing to learn more and more each day about swine flu. The pure sample of virus that we have isolated, together with its genetic fingerprint, will be important resources as scientific organisations join forces on the development of an effective vaccine.
"The rapid assessment of this virus will ultimately help us to make future decisions regarding the health implications of swine flu."
The UK Government has contracts in place with GlaxoSmithKline and Baxter for 132m doses of pandemic vaccine once one becomes available.
The HPA's National Institute of Biological Standards and Control, in Potters Bar, Hertfordshire is the only centre in the UK and one of a handful around the world developing vaccine prototypes for the European vaccine manufacturers.
The HPA's Centre for Emergency Preparedness and Response in Porton Down, as well as the National Institute for Medical Research (NIMR) and Veterinary Laboratories Agency (VLA) are also involved in the work.
Margret Chan, Director General of the World Health Organisation has said preparations for a pandemic have never been better but she warned global scientists not to take their 'eye off the ball' with the H5N1 avian flu virus. This virus is still circulating in birds and poultry in Asia and had thought the most likely flu virus to cause a pandemic.
Even though H1N1 now poses a greater threat, it is not known how the avian flu virus will act during a pandemic, she said.
It is feared that the H5N1 virus, which has proved very deadly in humans but not been passed between people, could mix with the milder but more transmissible H1N1 swine flu to create a new virus.
Worldwide there have been more than 2,300 confirmed cases of H1N1 with 44 deaths.
Meanwhile the European drugs regulator has announced that stockpiles of the antiviral drug Tamiflu can be safely used for another two years once it has passed it's current five-year shelf life if an official pandemic is declared. This will have the effect of extending the global stock of the drug in the event of a pandemic.
All new Tamiflu capsules will have a seven year shelf life, The European Medicines Agency has said.
Britain already has enough Tamiflu for half the population and this is being increased to 80 per cent.