A city council is considering using 19th century catacombs to store the bodies of swine flu victims if the outbreak worsens, it was confirmed today.

Exeter city council has identified the empty underground burial chambers, currently used as a tourist attraction, as a potential mortuary.

A council spokesman said the plan would be implemented if the crematorium and cemeteries could not keep up with funeral demands.

"We have some empty catacombs in an old cemetery in the city," he said. "These are 19th century underground burial chambers which are normally a tourist attraction. They can, however, be safely used for their original purpose and allow us to temporarily store bodies in the remote possibility that the need should arise."

So far at least 31 people have died in the UK after contracting the virus. Yesterday, the World Health Organisation said 800 people had now died worldwide from the H1N1 virus and as many as 2 billion people could eventually be infected.

Doctors have warned that NHS intensive care wards could be overwhelmed by severely ill swine flu patients if infection rates climb rapidly.

The growing pressure on critical care beds was underlined this week when a pregnant 26-year-old was flown from a hospital in Kilmarnock to Sweden for life-saving treatment because of a shortage of equipment in Britain. Sharon Pentleton's family said she was gravely ill, but her doctors believe she has a good chance of recovery.

According to Dr Alan Hay, director of the WHO's London-based world influenza centre, the first wave of UK infections is likely to peak within the next week or two before re-emerging in the winter.

Research published in the journal Anaesthesia suggests that when the peak comes, demand for intensive care beds could outstrip supply by 130% in some regions, while the demand for ventilators could exceed supply by 20%. Paediatric facilities are likely to become "quickly exhausted" as hospitals confront "massive excess demand", according to experts in intensive care and anaesthesia from the University of Cambridge, the Intensive Care Society and St George's Healthcare NHS trust in London.

The Department of Health said the NHS was prepared for the pandemic. "Guidance has been issued which contains information for primary and secondary care services in the UK on managing surge capacity and the prioritisation of services and patients during a widespread influenza outbreak," a spokesman said.