The UK is a world leader in sequencing SARS-CoV-2, the virus that causes COVID-19. Of all the coronavirus genomes that have been sequenced in the world, nearly half have been sequenced by COVID-19 Genomics UK Consortium (Cog-UK). The consortium began life on March 4 when Sharon Peacock, a professor of public health and microbiology at the University of Cambridge, emailed a handful of scientists and asked for their help. The Conversation spoke to Professor Peacock about that day and what happened after.