The emergence of the Brazil Covid variant in the UK could lead to the end of lockdown being delayed or even reversed, a top scientist has suggested.
SAGE advisor Graham Medley said there was always a risk "we might have to go backwards" when variants of concern emerge here.
It comes after a second expert warned there were concerns the P.1 variant might "evade" antibodies and make the vaccine "less potent".
Boris Johnson has announced a four-stage plan for lifting lockdown, in which he has insisted he does not want to go backwards.