The work is being carried out at the government's high-security Porton Down laboratory complex in Wiltshire by a team of more than 200 scientists.
They have drawn up a threat list of animal viruses that are capable of infecting humans and could in future spread rapidly around the world.
Which of them will break through and trigger the next pandemic is unknown, which is why it's referred to only as "Disease X".
Sky News was escorted around the site, which is run by the UK Health Security Agency, to see the work being done in high-containment labs.
Fascinus 1 points 1.7 years ago
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