This feared strain has since February been found in wild birds in seven of Germany's states, stretching from the Baltic Sea to Lake Constance on the Swiss border.

It reached Berlin late last month when a dead buzzard found on the balcony of an apartment block in the capital was confirmed to have had this form of the virus.

Three cats and a stone marten on the Baltic Sea island of Ruegen were also infected with the most dangerous form of H5N1, which has been responsible for more than 100 human deaths, mainly in Asia, since 2003.

The discovery of the disease in mammals sparked fears here that it could spread to humans more easily, but World Health Organisation experts have said this seemed unlikely.

The country's poultry industry complained last month that it has already lost millions of dollars because consumers were scared to eat poultry.

Reinking said the outbreak in Leipzig marked the first time that a poultry farm in Germany had been touched by a form of H5 bird flu since 1959, when the virus was registered.

The Scottish Executive said restrictions had been put in place around Cellardyke, east of Anstruther.

If the disease is confirmed as the deadly H5N1 strain there may be further restrictions set up.

The dead bird was found near the coast in an emaciated state. Samples were being sent for analysis at the EU's bird flu laboratory in Weybridge, Surrey.

An executive spokesman said: "In accordance with a recent EU decision the Scottish Executive is putting in place a protection zone of a minimum of three kilometres radius and a surveillance zone of 10 kilometres.

"Keepers of birds in the protection zone are being instructed to isolate their birds from wild birds, by taking them indoors where ever possible."

Measures to restrict the movement of poultry, eggs and poultry products from these zones will be brought into effect immediately.

Officials stressed that there was no reason for public health concern.

It is understood that the government's national emergency committee Cobra will meet on Thursday.

Representatives from Defra, the Scottish Executive, the Department of Health, the Cabinet Office and 10 Downing Street are expected to attend.

The H5N1 virus does not at present pose a large-scale threat to humans, as it cannot pass easily from one person to another.

However, experts fear the virus could mutate to gain this ability, and in its new form trigger a flu pandemic, potentially putting millions of human lives at risk.

According to the National Farmers Union Scotland, the Scottish poultry industry produces 127,000 tones of meat and 740 million eggs. However, there are thought to be no poultry farms in the immediate area of flu case.

Chief Veterinary Officer for Scotland Charles Milne said: "Whilst disease has yet to be confirmed, this is an important development.

"Bird keepers outside the protection zone should redouble their efforts to prepare for bringing their birds indoors if that becomes necessary.

"They must also review their biosecurity measures to ensure that all possible precautions have been taken."

Liberal Democrat leader Sir Menzies Campbell, in whose Fife North East constituency the bird was found, said he would follow the situation "very closely".

High alert

He said: "I have spoken directly to the (agriculture) minister, Ben Bradshaw, who has told me there cannot be final confirmation until tomorrow.

"I have his assurance that all necessary steps will be taken and that there is no health risk to humans."

First Minister Jack McConnell said he had spoken to other ministerial offices and was being kept informed of the situation.

Mr McConnell was notified whilst on an engagement in Washington as part of his involvement in Tartan Week.

BBC Scotland rural affairs correspondent Ken Rundle said that whilst the poultry industry would be on high alert, there would be relief that the virus had been found in a wild bird and not on a poultry farm.

BBC medical correspondent Fergus Walsh added that concerns over the case should not get out of proportion.

He said it could mean a potential crisis for the poultry industry, but not for humans.

Denmark recorded its first case of the potentially deadly H5N1 avian flu virus last month.

The strain has already been found in Europe in Switzerland, Poland, Serbia-Montenegro and Albania.

France recorded its first case in February.

Dr David Nabarro, the UN bird flu co-ordinator, told News 24: "Over the last few weeks we've seen swans and other birds dying in Western Europe and being found to have this virus, H5N1, on board.

"So, it's quite to be expected you have a case appearing in Scotland."

Palestinian authorities have decided to cull 500,000 birds in a three-kilometre (two-mile) radius around infection sites, half of which have been killed with the rest to be done "in a few days", he said.

The H5N1 virus was detected last month in birds in the Gaza Strip, as well as on Israeli farms and Jewish settlements in the occupied
West Bank.

Israel has said it has contained its outbreak but fears a new wave of infections from the Gaza Strip and Jordan, where the virus has also been found.

No human cases have been reported in Israel or the Palestinian territories.

But Manenti and Food and Agriculture Organisation project manager Luigi Damiani both expressed concern about the cull's impact on the Gazan economy and Palestinians' diet, saying Israel should reopen the Karni goods crossing.

"One specific concern is the fact that poultry constitutes the primary source of protein in the Gaza Strip and with the Karni crossing closed we are concerned about the nutritional consequences on the population," said Manenti.

Israel has only opened the Karni goods crossing, the only such crossing between Gaza and Israel, intermittently since the start of the year, with the UN warning of a food shortages even without the bird cull.

Manenti said that 30,000 Gazan poultry farmers would be affected by the cull, meaning that, with their families, some 200,000 people inside the impoverished territory will be affected, or 15 percent of the population.

Damiani said the World Food Programme was planning to distribute tinned fish in Gaza to make up for the lack of protein while suggesting Israel lift the ban on Palestinians fishing more than six nautical miles (11 kilometres) from shore.

"It's sardine season now and they're cheap enough for the Gazan population to eat," he said.

"We haven't changed our view that right now, there is not a safety concern, not a public health concern," she said. "But what we need to do is understand how benzene forms and to ensure the industry is doing everything to avoid those circumstances."

The admission contradicted statements last week, when officials said FDA found insignificant levels of benzene.

In fact, a different study found benzene at four times the tap water limit, on average, in 19 of 24 samples of diet soda.

Tarantino said chemists may have overestimated the amount of benzene and that levels in diet soda were still relatively low compared with other sources of benzene exposure.

The samples were collected as part of the FDA's ongoing Total Diet Study, which looks for contaminants and nutrients in many foods and beverages.

FDA has been doing a separate study of benzene in soft drinks, but it is not ready to release the results, Tarantino said.

The Environmental Working Group has accused the FDA of suppressing information about benzene in soft drinks.

"If they're so confident the situation is not a safety risk, they need to release the data to prove it," said Richard Wiles, the group's senior vice president. "The only data available to the public contradict their claim."

Benzene, a cancer-causing chemical linked to leukemia, can form naturally and is found in forest fires, gasoline and cigarette smoke. It's widely used in industrial production to make plastics, rubber, detergents, drugs and pesticides.

Benzene can also form in soft drinks made with Vitamin C and sodium or potassium benzoate. Heat, light and shelf life can affect whether benzene will form, according to FDA.

A spokesman for the American Beverage Association said the amount of soft drinks people consume is far less than the amount of tap water they are exposed to.

"You can crunch the numbers any way you want; it's still adding up to safe products," said the spokesman, Kevin Keane. "We're going to continue to work with FDA to ensure the safety of our products."

Chernobyl reactor number 4 in Ukraine was ripped apart by an explosion on 26 April 1986, and burned for 10 days. It disgorged a massive amount of radioactivity - up to 14 exabecquerels (14 × 1018 becquerels) - over Europe and the rest of the world.

Last September, the IAEA and the WHO released a report which claimed to reveal "the true scale of the accident". Its headline conclusion that radiation from the accident would kill a total of 4000 people was widely reported (New Scientist, 10 September 2005, p 14), but that figure is now being challenged. In a report this week for the Green group in the European Parliament, Ian Fairlie and David Sumner, two independent radiation scientists from the UK, say that the death toll from cancers caused by Chernobyl will in fact lie somewhere between 30,000 and 60,000.

They accuse the IAEA/WHO report of ignoring its own prediction of an extra 5000 cancer deaths in the less contaminated parts of Ukraine, Belarus and Russia, and of failing to take account of many thousands more deaths in other countries, where more than half of Chernobyl's fallout ended up. "It is poor scientific practice to issue figures which only reflect part of the real situation," Fairlie says.

Zhanat Carr, a radiation scientist with the WHO in Geneva, says the 5000 deaths were omitted because the report was a "political communication tool". "Scientifically, it may not be the best approach," she admitted to New Scientist. She also accepts that the WHO estimates did not include predicted cancers outside Ukraine, Belarus and Russia. The health impact in other countries will be "negligible", she says, adding that there is no epidemiological research showing otherwise. The WHO "has no reasons to deliberately mislead anyone", she insists. "WHO's position is independent, free from political issues, and based on scientific evidence of the highest quality." The IAEA refused to comment.

Fairlie and Sumner's accusations are backed by other experts. The IAEA/WHO report "misrepresents reality by significantly underestimating the number of cancer deaths", says Timothy Mousseau of the University of South Carolina in Columbia. A paper co-authored by Mousseau and published this week in Trends in Ecology and Evolution (DOI: 10.1016/j.tree.2006.01.008) points to studies suggesting that fallout from Chernobyl has already caused germline mutations in animals and plants.

Elizabeth Cardis, a radiation specialist from the WHO's International Agency for Research on Cancer in Lyon, France, says that 30,000 to 60,000 cancer deaths is "the right order of magnitude". She is due to publish a study later this month that will estimate the number of excess cancers attributable to Chernobyl amongst 570 million Europeans. Though they will be difficult to detect, as they will only form a tiny proportion of the millions of cancer deaths from all causes, this doesn't mean that they should be ignored, Cardis says. "They are real people who suffer from the accident."