SARS-CoV-2 has caused over 2 million deaths in little over a year. Vaccines are being deployed at scale, aiming to generate responses against the virus spike. The scale of the pandemic and error-prone virus replication is leading to the appearance of mutant viruses and potentially escape from antibody responses. Variant B.1.1.7, now dominant in the UK, with increased transmission, harbours 9 amino-acid changes in the spike, including N501Y in the ACE2 interacting-surface. In this study, the authors examined the ability of B.1.1.7 to evade antibody responses elicited by natural SARS-CoV-2 infection or vaccination. They mapped the impact of N501Y by structure/function analysis of a large panel of well-characterised monoclonal antibodies. B.1.1.7 is harder to neutralise than parental virus, compromising neutralisation by some members of a major class of public antibodies through light chain contacts with residue 501. However, widespread escape from monoclonal antibodies or antibody responses generated by natural infection or vaccination was not observed.