The health secretary has said that England's lockdown means "we've got this virus back under control" - but warned continued vigilance is needed.
© GettyEngland's second lockdown is due to be replaced by a strengthened tiered system on Wednesday
Speaking at a Downing Street news conference, Matt Hancock acknowledged that the new restrictions have been tough - but stressed that the stricter measures have been working.
Although the national lockdown is due to end on Wednesday, he warned: "We don't have much headroom. We can't risk letting cases rise again, especially into Christmas and with the flu season around the corner."
The health secretary stressed the need for a return to the tiered system seen before the second national shutdown, saying that "while we can let up a little, we can't afford to let up a lot".
Mr Hancock said that around one in three people have no symptoms of the virus but can still infect others, adding: "That is why even as we ease these national restrictions we've got to keep some restrictions in place.
"So while we can let up a little, we can't afford to let up a lot.
"The success of our collective efforts means that from Wednesday everyone in England, even those in Tier 3, can have some greater freedoms but we don't have much headroom."
Speaking earlier, Boris Johnson again defended the toughened up tiers system which is due to come into effect when the lockdown ends, amid the prospect of dozen of Conservative MPs voting against the measures on Tuesday.
"We can't afford to take our foot off the throat of the beast, to take our foot off the gas, we can't afford to let it out of control again," the prime minister said.
"The tiering system is tough, but it's designed to be tough and to keep it under control.
"I know that lots of people think that they are in the wrong tier and I understand people's frustration."
The government has published its impact assessment of the tiered approach in a bid to win round potential rebel MPs.
Mr Johnson has said that mass testing and the rollout of any approved coronavirus vaccines will offer areas a way out of the harshest measures.
The PM said rolling out widespread testing for the virus "in ever greater numbers" would - along with vaccines - allow the UK to "push the virus down and to open up the economy to allow areas to come down in the tiers that they are in, steadily making progress that way".