The Department of Health today promised to buy enough bird flu vaccine to immunise the entire population of Britain if and when a pandemic advances on Europe.

Sir Liam Donaldson, the Chief Medical Officer, made the announcement as two new outbreaks of the lethal H5N1 strain of the virus were confirmed in poultry, one in Romania and another in Russia.

Although the virus has yet to transform into a form which is readily passed between humans, scientists believe such a mutation is inevitable and have warned that between two million and 50 million people could die. In the UK, Sir Liam has predicted at least 50,000 deaths.

Sir Liam was updating the UK Influenza Pandemic Contingency plan, first issued in March when the first 14.6 million courses of the Tamiflu anti-viral drug were ordered.

Today's promise would put Britain ahead of other countries in its plans to protect its own citizens. The proposal far exceeds guidance from the World Health Organisation that every nation should stockpile enough vaccine to treat 25 per cent of its population.

As soon as the precise structure of the expected human form of the virus is known, the operation will begin to produce 120 million doses of vaccine - the equivalent of two per person - necessary to immunise the entire population.

Developing the vaccine is, however, likely to take several months. By the time the vaccine has been produced, the first wave of the pandemic is likely to have died down naturally. It would instead be available to fight the second wave.

Scientists have also warned that rich nations will not combat the virus by merely protecting their own: if the virus reaches poor countries, especially in Africa where poultry farmers live in close contact with their livestock, new forms of the disease will emerge.

"We can’t prevent a flu pandemic, but we can reduce its impact," Sir Liam told a briefing at Whitehall, London, today.

"One of the most effective countermeasures we can take against a flu pandemic is to make sure we develop and manufacture a vaccine as quickly as possible.

"We will use this vaccine to immunise the UK population and reduce the impact of a pandemic on society."

As a second strand to today’s updated contingency plan, the Department of Health issued an information pack for GPs to help them to prepare for the pandemic.

Sir Liam said: "Planning to combat pandemic flu is our number one priority. We regard pandemic flu as public health enemy number one and we are on the march against it.

"With good planning and preparation we can reduce the impact of pandemic flu on the health of our population."

Fears that the pandemic will hit the UK have grown in the last week after cases of the potentially lethal H5N1 strain of bird flu were confirmed in Romania, Turkey and Russia.

Bird flu has also been confirmed in Greece, but it is not yet known if this is the dangerous H5N1 strain or a less virulent form.

Sir Liam was speaking as tests confirmed that the H5N1 strain had been found in a swan and hen in a second location in Romania’s eastern Danube Delta region. Romanian authorities have killed all farm birds in the area.

In Russia, tests have shown the presence of genetic material of H5N1 from dead chickens from the village of Yandovka in the Tula region, south of Moscow. The village has been quarantined and all 3,000 poultry killed.

Jack Straw, the Foreign Secretary, said that Europe has so far managed to tackle isolated outbreaks "swiftly and efficiently".

But there are growing fears that the disease, which is carried by migrating birds, will cross into eastern Africa and the Middle East, where poor poultry farmers will be unable to report, manage or contain it effectively.

A meeting of EU health ministers in Hertfordshire today and tomorrow will also discuss bird flu. There are proposals for a simulation exercise later this year to test the response of countries to the emergence of the deadly strain.

Flu facts

* In Turkey, 8,000 turkeys, chicken and geese have been exterminated

* In Romania, 22 more dead birds have been found on lakes in the Danube delta region. Around 50 sick swans and a duck with antibodies to the H5N1 strain have already been found on lakes near the border with Ukraine

* 3,000 birds slaughtered in seven farms in Yandovka, a village in the Russian province of Tula, to the west of the Ural mountains, carrying a H5N1 strain of the virus apparently spread by migrating ducks

* In Macedonia, all 10,000 chickens were culled in the small southern village of Mogila, near Bitola, after the discovery of Newcastle Disease - a common and contagious poultry ailment which can cause mild influenza in humans. The cull was opposed by farmers after one bird displayed irregular symptoms and was tested for bird flu

* In Greece, test samples from a lone turkey found dead with bird flu in Oinouses, a remote island in the north Aegean, have come back negative for the H5N1 strain

* In China, 2,600 birds have died from bird flu at a breeding facility in Hohhot, in Inner Mongolia. Officials said the outbreak, the country's first in two months, had now been controlled

* Bavaria has banned all poultry from being kept outdoors until the end of the migration season in mid-December. Germany today decided to immediately confine all of its farm poultry to indoor pens.

* Iran, which is on the migration pathway of infected birds, has banned shooting fowl and is stocking up on vaccines

* Spain's health ministry has ordered 6 million doses of anti-viral medicine, enough to trat 15 per cent of its population

* Shares in GlazoSmithKline, which manufactures the anti-viral drug Relenza, rose to a three-year high. Relenza is similar to Tamiflu in its effects of reducing the severity of influenza, but rather than being taken in pill form it is inhaled as an aerosol

* Taiwan has said it could produce up to a million doses of Tamiflu within five months if manufacturer Roche agrees to relax controls on its licence

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