Smallpox

This agonising, disfiguring and often fatal disease has been with us for most of our history. It was, fortunately, eradicated by a World Health Organisation programme in the 1970s - but the threat didn't end there. The virus still exists in labs in the US, Russia and - reputedly - North Korea, raising the terrible spectre of its use in biological warfare.

Smallpox was once known as the 'scourge of the earth' - evidence of its scarring was found on the mummy of Rameses V dated at 757 BC, and the horrors of the virus were vividly described by the ancient Greeks. Before the development of vaccination in the eighteenth century, most adults would have had - and survived - the disease at some time in their lives. No one was safe. Elizabeth I suffered from smallpox aged 29 and the fact that she wore a wig and thick facial makeup is often attributed to the hair loss and scarring caused by the disease. In the 17th century, no fewer than eight of Europe's ruling monarchs died from smallpox.

This programme documents the WHO's unique achievement in wiping out the disease worldwide, but also considers the threat caused by the continuing existence of the virus in vitro. Could the disease which felled mighty empires as far back as 1000BC be used in modern day warfare?