Boris Johnson warned harsher lockdown measures will 'probably' be needed due to the mutant Covid strain Keir Starmer condemned the PM for 'delaying' and insisted national lockdown should happen within 24 hours Mr Johnson has urged parents still to send their children back to primaries that are set to reopen tomorrow PM said he had 'no doubt' that schools were safe but refused to rule out full shutdown in the weeks to come Ofsted boss Amanda Spielman has delivered stark warning that children's learning cannot be 'furloughed' Left-wing councils join revolt against Government plans as National Education Union says schools are not safe