Summary of evidence from the U.K. This document has been prepared by the European Molecular Biology Laboratory to provide a summary of epidemiological information for public health officials and governments. The lead author is Dr Moritz Gerstung, of EMBL’s European Bioinformatics Institute (EMBL-EBI) at the Wellcome Genome Campus in the United Kingdom. Other contributors include Deputy Director General and EMBL-EBI Director Dr Ewan Birney FRS and EMBL-EBI Director Dr Rolf Apweiler. The B.1.1.7 lineage was first discovered on September 20 in Kent by the U.K.’s Coronavirus Genome consortium COG-UK, which has sequenced more than 170,000 SARS-CoV-2 genomes [1,2]. It has since spread to nearly every British local authority and 57 other countries [3]. While B.1.1.7 is not evidently causing more severe disease [4], it is approximately 30-50% more transmissible as evidenced by epidemiology [5,6] and contact tracing [7]. This higher transmissibility has led to a massive surge in cases in England, which has pushed the health care system to its limits and led to declaration of a third national strict lockdown [8] on January 4, 2021.