Millions of people in the UK are from Monday allowed to hug their loved ones and travel overseas after the biggest easing of lockdown restrictions since last summer.
Across England, Wales and most of Scotland, indoor hospitality venues, cinemas and museums will open their doors for the first time in months.
People are allowed to meet indoors in limited numbers, while the ban on foreign travel has been lifted, although quarantine is still required for most destinations.
Hugs between people from different households will be allowed for the first time in a year.
The Indian variant continues to spread in the UK, with surge testing taking place in hotspots such as Bolton in Greater Manchester and parts of London, Sefton on Merseyside and Worcestershire.
Prime Minister Boris Johnson said everyone must continue to “play their part” and take a coronavirus vaccine.
“Together we have reached another milestone in our road map out of lockdown, but we must take this next step with a heavy dose of caution,” he said.
“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 there was no need to delay the plan to end most restrictions on June 21, despite fears of a surge in cases fuelled by the Indian strain.
“The current data does not indicate unsustainable pressure on the NHS and our extraordinary vaccination programme will accelerate – with second doses being bought forward to give the most vulnerable maximum protection,” Mr Johnson said.
“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.”
Business Secretary Kwasi Kwarteng said on Monday it was still an option to delay the final stage of the government's road map because "we don't know what coronavirus will do".
“Yes, things are being opened up but people should have common sense and use judgment,” he told Sky News.
“People shouldn’t be running away getting too exuberant.”
Last week, the country’s vaccination programme was brought forward to protect the over-50s and clinically vulnerable people from the Indian variant as measures were lifted.
More than 20 million people are fully vaccinated in Britain, which is one of the world’s worst-hit countries with more than 127,000 Covid-19 deaths.
Cases of the Indian strain rose from 520 to 1,313 last week, with clusters in the north-western towns of Bolton and Blackburn.
Health Secretary Matt Hancock said the government could stay on course thanks to a high degree of confidence that vaccines would stand up to the strain.
He said the vast majority of people in hospital in Bolton with the new variant were eligible for vaccination but had not come forward.
“It could spread like wildfire among the unvaccinated groups,” he said.
Ministers urged people not to visit amber list countries despite overseas trips now being legal.
Under the new traffic light system that came into force on Monday, countries are rated as green, amber or red based on the risk of importing coronavirus into the UK.
Mr Hancock said the green list offered "a safe way” to travel.
“People should not travel to amber or red list countries unless it’s absolutely necessary and certainly not for holiday purposes,” he said.
Mr Johnson has come under pressure from experts and opposition politicians for failing to restrict travel from India sooner, when Covid-19 cases were surging across the subcontinent.
Last week, the prime minister committed to a full, independent public inquiry into his government's handling of the coronavirus.
He has been accused of dithering over a third national lockdown in early January, as hospital admissions and death rates were increasing sharply.
But the Conservative government's popularity has been boosted by a successful vaccination campaign and a strong showing in local elections in England.
Vaccines Minister Nadhim Zahawi said "one of the highest vaccine uptake rates in the world" had been crucial to keeping the virus at bay.
