A severe flu pandemic could kill more than 63,000 people in Scotland within a few weeks and overwhelm mortuaries and crematoriums, an official study has concluded.
The document, released to the Guardian under freedom of information regulations, also warns that at least 5,100 people in Scotland could die even if the flu virus was relatively mild and infected only a quarter of the population.
It warns that mortuaries, crematoriums and cemeteries could be forced to operate round the clock, with old warehouses, council buildings, refrigerated lorries and specialist inflatable mortuaries being requisitioned to temporarily store the dead.
The previously unpublished study was written last year to help councils and health authorities plan for a pandemic, before swine flu hit the UK, leaving at least 31 people dead and infecting an estimated 85,000 people since April.
The Scottish government's study bases its mortality estimates on four scenarios ranging from a relatively mild flu virus infecting 25% of the population and killing 0.37% of those infected, to an "exceptional" and more lethal pandemic affecting half the population.
The relatively mild virus would leave about 5,100 dead, a figure that is very close to the 0.35% mortality rate used to make last week's worst-case prediction that swine flu could kill 65,000 across the UK this winter.
The Scottish study warns that a very severe outbreak – worse than the last two pandemics in the late 1950s and late 1960s – might affect half the population and kill 2.5% of those infected. While unlikely, that would kill 63,700 people in Scotland alone.
The report, which is supported by detailed region-by-region death rates and other studies on mortuary capacity, warns that in such a severe pandemic Scotland's 32 local councils and its hospitals would be stretched to breaking point.
With deaths expected to peak sharply within six to seven weeks of an outbreak, crematoriums would in many areas have to operate 24 hours a day, while every town and city would require temporary mortuaries and body storage facilities. Islands such as Shetland and the Western Isles would face severe problems, particularly with transport problems during winter.
The documents argue strongly against providing mass graves because it would be extremely distressing to the families, be politically difficult and would lead to legal action by relatives to exhume bodies and rebury them in single graves after the pandemic.
But at least one council, Glasgow, which could see 27,500 deaths in the worst-case scenario, has confirmed it has common ground available if mass burials are needed. Emergency planners in northern Scotland have confirmed they may use refrigerated lorries in extreme circumstances.
Jon Harris, strategy director for the Scottish councils umbrella body Cosla, said local authorities were still drafting contingency plans for an outbreak and confirmed that if death rates did surge some councils would be unable to cope on their own.
However, he stressed that the worst-case scenario was "very unlikely to happen. The virus is still very mild and the number of fatalities is still deemed to be relatively small."
A Scottish government spokeswoman confirmed the scenarios were for planning purposes, and not linked to the current pandemic.
She said: "Planning is a part of normal government and it is right that we work with a range of partners to ensure that we are as prepared as possible for severe situations.
"Many of the measures in the guidance are not expected to be needed and it is important to stress that the vast majority of people who have H1N1 will experience mild symptoms and make a full recovery."
