The UK's health services could collapse in the event of a terrorist attack as tens of thousands of "worried well" report for treatment, government advisers fear.
Restricted documents leaked to The Times Higher reveal that behavioural scientists are being asked for guidance on "how to influence people... to avoid anxious individuals swamping" the National Health Service after an attack.
Officials also want researchers to create predictive models to help plot the behaviour of crowds after an attack using chemical weapons or a so-called dirty bomb.
The officials' fears chime with the conclusions of one of the UK's leading experts on mass hysteria. In a paper due to be published in the Journal of Mental Health , Simon Wessely, a professor at the Centre for Military Health Research at King's College London, says that "it is very unlikely that stretched emergency services will be able to cope" with the large number of people likely to seek medical aid even if they have not been contaminated by an attack.
The Home Office met 22 human behaviour experts - only three of them university researchers - last month to discuss its research needs. The meeting was held during a secretive gathering in London at which more than 250 researchers were invited to bid for research projects under an annual £10 million chemical, biological, radiological and nuclear science and technology programme.
Researchers were told of five priority areas for research, including guidance on how to limit the post-traumatic stress of any attack and how to ensure effective risk communications to the public "to instil trust".
The meeting was chaired by Paul Wiles, chief scientific adviser to the Home Office and director of research and development. Also present was Anna Higgitt, senior clinical medical officer at the Department of Health, and a representative of the Defence Science and Technology Laboratory, the science wing of the Ministry of Defence.
A researcher who attended the meeting said that there were growing concerns in Whitehall about the "worried well" phenomenon. He referred to the "Goiania incident" in Brazil in 1985, when a radioactive source from an abandoned medical centre was opened. It contaminated 249 people, four of whom died, but a total of 112,000 people had to be treated.
The researcher said that the Government, by focusing too much on "what to do when the shit hits the fan", was failing to consider the climate in which the public is hypersensitive to risk.
"There is not enough about the here and now," he said. "People are generally maintained in a state of concern, right across the political spectrum, about obesity, drinking, smoking and so on."
Professor Wessely, who was not present at the meeting, added: "It is quite correct that the first thing for a government to do is to make sure it has the right kit - the right antidote, the right vaccinations.
"But then you have to think about how to manage the social and psychological consequences of these incidents. This type (of preparation) is also life-saving, as one of the causes of death in incidents is panic."
A Home Office official said: "The Home Office is inviting proposals to help us better understand how people might respond to such an incident. General research around emergencies shows that mass hysteria or panic rarely occurs where people are clear about what they should do.
"We believe that the key to any response is providing information on the threat as soon as it is understood, including what actions those caught in the incident should take. Local broadcasts would be made by the emergency services, backed up by announcements through the media.
"The research proposals will assist us in deciding how best to deliver the right messages to the public."