The Labour leader has called for a "circuit-breaker" lockdown of up to three weeks in England to tackle soaring coronavirus cases.
Sir Keir Starmer said we are 'at a decisive moment in the fight' against the virus.
His demands come on the same day 143 new Covid-related deaths have been confirmed - the biggest rise in four months.
He told his 994.7K Twitter followers: "We are at a decisive moment in the fight against the coronavirus. That’s why I'm calling for a circuit break in England - to protect the NHS, fix testing and get control of the virus.
Speaking at his first monthly conference, Sir Keir said there was "no longer time to give the prime minister the benefit of the doubt".
"The government's plan simply isn't working - another course is needed," he added.
His plan would "not mean schools closing" but it should "run across half-term to minimise disruption".
But, he said it would mean that "all pubs, bars and restaurants would be closed" and compensated "so that no business loses out because of the sacrifices we all need to make".
Sir Keir said he was spurred into action by SAGE documents last night.
They showed SAGE urged the PM to go much further than the new "three-tier" lockdowns in England. SAGE shortlisted five urgent options, including a circuit-break, three weeks ago - but Boris Johnson only implemented one of the five.
After months of promising "constructive" opposition, Sir Keir declared: "The government has not got a credible plan to slow infections. It has lost control of the virus and it is no longer following scientific advice."
