Swine flu vaccines are being tested in thousands of volunteers
The European drugs regulator has given the go-ahead for one of the UK's swine flu vaccines.
An expert committee agreed that Pandemrix, made by GlaxoSmithKline, can be used in adults and children over six months old and pregnant women.
The decision removes one of the last obstacles to getting the immunisation programme under way although licensing still needs to be formalised.
The UK has bought 60 million doses of the vaccine.
In addition, there are contracts for an as yet unapproved vaccine, Celvapan, produced by Baxter.
It means the UK has provision for up to 132 million doses - enough for every person in the country.
We plan to start vaccination in October, subject to vaccine being licensed and manufacturers' delivery schedules
Department of Health spokesman
A vaccine made by Novartis, Focetria, has also been recommended for licensing by the European Medicines Agency - but this is not planned to be used in the UK.
Final marketing authorisation for the vaccines still needs to be signed off by the European Commission and is expected "as soon as possible".
The EMEA said they were working with Baxter on some ongoing issues about their vaccine but hoped to be able to resolve that next week.
The vaccines have undergone an accelerated approval process as "mock-ups" of the vaccine had already been developed in preparation for a pandemic and tested in 6,000 people.
Manufacturers have worked quickly to add the swine flu H1N1 strain to the mock versions.
Early trial data had suggested good immune responses with just one dose of the vaccines.
However, the EMEA is recommending two doses are given three weeks apart for both vaccines, but may revisit that decision as more clinical trials are carried out.
The number of new cases of swine flu in England has almost doubled over the last seven days to 9,000, official figures show.
In Scotland, the new weekly figures showed a slight increase from 6,180 to 7,034.
Across the UK there have been 82 deaths.
Although the figures are rising, they are as yet far short of the 100,000 cases a week seen in July.
Officials are still predicting a second wave of swine flu as winter approaches.
But they hope to begin a vaccination programme sometime next month.
Like traditional seasonal flu vaccines, the GSK swine flu vaccine is being made in eggs
The H1N1 strain is injected into eggs where it multiples before being harvested, purified and chemically inactivated so it cannot cause flu but can prompt an immune response
The resulting viral particles are then tested and added to the vaccine
It can take up to two eggs to produce one dose of vaccine
The other method for making vaccines uses mammalian cell cultures to grow the vaccine - this is the approach being taken by Baxter
High-risk individuals and front-line NHS staff have been prioritised for the vaccine.
Those eligible include anyone aged between six months and 65 years who usually gets the seasonal flu jab because of a chronic illness such as asthma, pregnant women, and people who live with those whose immune systems are compromised, such as cancer patients or people with HIV/AIDS.
It will also be offered initially to people aged 65 who are at high-risk of complications because of an underlying illness.
A further decision on who else may be vaccinated once these groups have been targeted is yet to be made.
A spokesman for the Department of Health said: "This is a welcome step forward in our plans for tackling swine flu - but we are still dependant on production and delivery of sufficient vaccine to start protecting people.
"We plan to start vaccination in October, subject to vaccine being licensed and manufacturers' delivery schedules.
"This is not the Department of Health's schedule - it is led by the manufacturers."
Professor Steve Field, chair of the Royal College of GPs, said practices needed to prepare to call in the high-risk groups for vaccination.
"The scientists are saying it should be targeted at high-risk groups because the illness is mild but my understanding is that is being reviewed regularly.
"My hunch is it will be rolled out to more people."
Concerns have been raised about the safety of the vaccines given the speed of the approval process.
But the EMEA stressed that decades of experience with seasonal influenza vaccines indicate that adding a new strain in should not substantially affect safety.
WHY TWO VACCINES?
The UK has agreed contracts for swine flu vaccine with GSK and Baxter
Having two contracts increases the number of doses available
Also because the Baxter vaccine is not made in eggs it can be used in people with an egg allergy
There are other differences between the vaccines -for example the GSK one contains an adjuvant
It minimises the risk of problems should one vaccine run into trouble during production or licensing
Both vaccines the Agency have recommended for licensing contain an adjuvant - a chemical which boosts the immune response - but this too has been tested in thousands of people, it said.
Further clinical trials are being done and Pandemrix is being tested in 9,000 children, elderly and healthy adult volunteers.
Data submitted to the regulator by GSK suggests the vaccine is generally well tolerated, with the most commonly reported side-effects being headache, joint pain, muscle pain, reactions at the site of the injection (such as pain and redness), fever and fatigue.
The first results from a trial of the vaccine in Germany suggested a good response after one dose.
The EMEA added that with all medicines, adverse events may be detected once the vaccine is used in large numbers of people.
UK regulators have set up a special portal on the website for reporting any problems with swine flu medicines and vaccines when they begin to be used.