Boris Johnson has issued a plea for people to use a “heavy dose of caution” as lockdown rules ease further on Monday.
Pubs and restaurants will be able to reopen indoors and the ban on foreign travel is lifted, allowing holidaymakers to jet off for some sun for the first time in months.
People will also be allowed to hug friends and family from different households for the first time since Covid restrictions were imposed more than a year ago.
But the Prime Minister urged the public to remain cautious despite the greater freedoms, as concerns mount over the spread of the Indian Covid variant.
Surge testing is being ramped up in hotspot areas and the vaccine rollout is being accelerated to prevent the new strain from derailing the route out of lockdown.
Top scientists have warned the UK faces a “perilous moment” as the Indian variant is feared to be up to 50% more transmissible than the Kent strain that ripped through the nation in the winter.
In a statement, Mr Johnson said: “Together we have reached another milestone in our roadmap out of lockdown, but we must take this next step with a heavy dose of caution.
“We are keeping the spread of the variant first identified in India under close observation and taking swift action where infection rates are rising.”
He said the “current data does not indicate unsustainable pressure on the NHS”, and that second vaccine doses are being accelerated to give the greatest protection to the most vulnerable.
He added: “But now everyone must play their part – by getting tested twice a week, coming forward for your vaccine when called and remembering hands, face, space and fresh air.
“I urge everyone to be cautious and take responsibility when enjoying new freedoms today in order to keep the virus at bay.”
Health Secretary Matt Hancock warned that the new strain could “spread like wildfire” among the unvaccinated as he urged people to get their jabs.
There have been more than 1,300 cases of the new strain, he said, but the “vast majority” of people hospitalised with the new variant Bolton have not taken the vaccine.
The Health Secretary said there had been no known deaths from the Indian variant in Bolton of somebody who has received both jabs.
He did not rule out imposing tougher local curbs to tackle the new strain or delaying the final lifting of restrictions on June 21 if necessary.
No decision will be taken on moving to step four of the roadmap until June 14.
However Mr Hancock hailed “new very early data” from Oxford University which said the existing vaccines work against the variant.
“That means that we can stay on course with our strategy of using the vaccine to deal with the pandemic and opening up carefully and cautiously, but we do need to be really very vigilant to the spread of the disease,” he told Sky’s Sophy Ridge On Sunday.
“We have a high degree of confidence that the vaccine will overcome.”
More than 20 million people have had both jabs, covering more than 38% of UK adults, while more than 69% have received at least one.
SAGE expert Sir Mark Walport warned it will be “extremely important” to keep an eye on the numbers over the next few weeks.
“And the problem is that the data takes some while to emerge, which is why there’s you know every grounds to be very cautious about the ability to open up in June,” he said.
“But I mean I think it’s fair to say it is a perilous moment. We have a variant that shows good evidence of being more transmissible and possibly significantly more transmissible.”
Labour’s Yvette Cooper, who chairs the Commons Home Affairs Committee, said the foreign holiday ban should not be lifted on Monday.
The Labour MP told the BBC: “The Government needs to slow down its plans.
“I don’t understand why it’s lifting some of its international travel restrictions tomorrow. I think they should be being much more cautious about that.”