Johnson qualified the COVID-19 pandemic as the biggest challenge the country faced since World War II, stressing that he does not underestimate the continuing problems.

"It is also true that we are making progress with fewer hospital admissions, fewer COVID patients. I see real signs now that we are passing through the peak, thanks to ... your good sense, your altruism, your spirit of community, thanks to our collective national resolve, we are on the brink of achieving the first clear mission, to prevent our national health service from being overwhelmed ... That is how and why we are now turning over the tide," Johnson said.

This is the moment of risk, since many people see the "apparent success" and begin to wonder "whether now is the time to go easy on social distancing measures," the UK prime minister warned.

Johnson said he understands how difficult it is to give up even temporarily on the basic freedoms, not see friends and loved ones, to worry about jobs.

"I understand your impatience, I share your anxiety ... I can see the long-term consequences of the lockdown as clearly as anyone. I entirely share your urgency, it's the government's urgency, and yet we should recognize the risk of the second spike, the risk of losing control of the virus," Johnson said.

Johnson added he was refusing to "throw away all the effort and sacrifice of the British people" and risk a second outbreak.

The United Kingdom has so far confirmed 152,840 COVID-19 cases, with the death toll exceeding 20,700. The quarantine is to last through May 7 at least.