UK Prime Minister Boris Johnson on Oct. 14 rejected Labour's call for an immediate 2-to-3-week-long national lockdown, but said he would "rule out nothing" for the future.
"Why did the prime minister reject that advice and abandon the science?" Starmer asked.
The prime minister said he adopted the three-tiered approach because "the disease is appearing much more strongly in some parts of the country than in others."
But he also said he would "rule out nothing" in combating the virus.
In his speech the previous day, Starmer launched a series of criticisms against the Conservative government.
"Three things are now clear," the Labour leader said. "The Government has not got a credible plan to slow infections. It has lost control of the virus. And it’s no longer following the scientific advice."
He called for circuit-breaker lockdown, possibly during schools' half term break.
Former Conservative leader Iain Duncan Smith called the speech "naked political posturing" and said the short lockdowns are more of a "business-breaker" than "circuit-breaker."
"We ended up with months of absolutely no business being able to operate, the Exchequer having to pile money out the door at a rate which has never been seen since we were at war in the second world war.
"All of these things cause huge consequences. So the idea of a casual 'Let's have a circuit-breaker over the half term' as though this is going to make a short sharp difference—it's not going to."
Duncan Smith also proposed in Parliament, and said he would do so again, that the government should look at the effect of antivirals in reducing the death rate of CCP virus patients.