SCIENTISTS yesterday warned that the swine flu outbreak that is now feared to have spread to more than 20 countries could infect four in 10 Europeans if it became a pandemic.
The '40pc at risk' warning came as the first British sufferers of the condition were named as Iain and Dawn Askham, a newly married couple from Falkirk, central Scotland, who returned from honeymoon in Mexico last week.
Their conditions are said to be improving, but doctors are monitoring possible new cases in Wiltshire, Derbyshire, Yorkshire and Wales.
And last night Californian governor Arnold Schwarzenegger declared a "state of emergency" for the state over the outbreak which has killed 149 people in Mexico.
So far, state and local officials have confirmed 13 cases of the swine flu in California. None have been fatal, although Los Angeles County Coroner's officials were investigating two deaths as possibly related to the disease.
Mr Schwarzenegger's proclamation allows the state to deploy additional resources to the Department of Public Health.
In London, the UK Government's Cobra emergencies committee, involving both Gordon Brown and Health Secretary Alan Johnson, met to discuss the outbreak
The potentially deadly virus has now been confirmed in seven countries, although only in Mexico where the outbreak originated has the condition proved fatal.
There, more than 150 deaths are thought to be related to swine flu, although only seven have been confirmed as being caused by the virus.
The US has announced 44 mild infections, while three people have the virus in New Zealand and six in Canada.
There have been two confirmed cases in Spain and one in Israel, and 15 other countries have said they are investigating possible infections.
Six people have been tested here.
World Health Organisation (WHO) experts are warning that the swine flu virus spreading around the world now cannot be contained. Professor Neil Ferguson, a WHO member at Imperial College, London, said that the virus would likely return later in the year even if it died away in the next few weeks.
"It is almost certain that... we will get a seasonal epidemic in the autumn," he said.
The WHO has raised its swine flu alert level to phase four on a scale that goes up to six, meaning the virus is now being passed between humans.
The organisation's assistant-general, Keiji Fukuda, said this represented a "significant step towards pandemic influenza".