People must continue to play their part in stopping coronavirus, Boris Johnson has said, as lockdown rules ease in England, Wales and most of Scotland.
Millions can now socialise indoors in limited numbers, hug loved ones and visit pubs and restaurants inside.
The ban on foreign travel has also been lifted and replaced with new rules.
Mr Johnson said: "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."
The rule changes come as the variant first identified in India continues to spread in the UK, with mass testing rolled out to hotspots including Bolton in Greater Manchester and parts of London and Sefton.
Mr Johnson said the government was keeping the variant "under close observation" and "taking swift action where infection rates are rising".
Business Secretary Kwasi Kwarteng told BBC Radio 4's Today programme he was "very confident" the government would be able to lift England's remaining restrictions on 21 June "but can't guarantee that".
He said: "There is flexibility here because we have another five weeks till the reopening and we will be revisiting the data.
"There will be different data - the variant will spread, perhaps, in different ways, we will have more information about the efficacy of the vaccine rollout, and then... a week before the 21st, we will take the decision."
Mr Kwarteng said he did not want to "stigmatise people" over vaccine hesitancy, but added: "We're not exactly where we want to be among certain communities but I think the take-up has been much greater in the last few months, and more and more people are convinced that this is the way to keep themselves and their families safe."
More than 6,200 people were vaccinated in Bolton at the weekend, where the Indian variant now makes up the majority of new cases. Prior to the push, about 10,000 people in the highest priority groups were yet to be vaccinated.
