Johnson apologized on Wednesday for attending a "bring your own booze" party in the garden of the prime minister's Downing Street office and residence in May 2020.
The U.K. was slower to impose widespread lockdowns than the U.S. and many other countries. A new report says the government's approach amounted to accepting a herd immunity strategy.
The test roll-out is intended to ease the reopening of England's economy. But the move was met with critics who say rapid testing is a waste of money because it could result in many false positives.
The German chancellor defended her government's decision to extend a COVID-19 lockdown into March, as she issued a stark warning about fast-spreading new strains.
Prime Minister Boris Johnson announces that pubs, bars and restaurants in England must close at 10 p.m. He also encourages people who are able to work from home to do so.
The prime minister, who spent three days in intensive care and another two weeks recovering from the disease, warned that any letup in efforts to halt it risked "a new wave of death and disease."
Foreign Secretary Dominic Raab said: "I'm confident he'll pull through." Meanwhile, the U.K. on Tuesday set a new high for COVID-19 deaths, with 786 succumbing to the disease.
"Over the course of this afternoon, the condition of the prime minister has worsened and, on the advice of his medical team, he has been moved to the Intensive," U.K. officials said.
Prime Minister Boris Johnson sought an early general election in the hope of gaining ground in Parliament in support of the question that has roiled British politics since 2016: leaving the EU.