Boris Johnson has urged the nation to "behave responsibly" as pub gardens reopen and restaurants resume outdoor dining in England.
In the next major step in the easing of England’s coronavirus lockdown, shops deemed non-essential are also reopening, as are hairdressers, indoor gyms, swimming pools, nail salons and zoos.
However, social mixing indoors remains heavily restricted, with around two in five adults yet to receive their first dose of a COVID-19 vaccine – and the vast majority yet to get both.
But a government source confirmed Mr Johnson would have his hair cut on Monday morning ahead of the prime minister leading tributes to Prince Philip in the House of Commons later.
Mr Johnson urged caution during the "major step forward" in the easing of England’s lockdown.
"I’m sure it will be a huge relief for those business owners who have been closed for so long, and for everyone else it’s a chance to get back to doing some of the things we love and have missed," he said.
"I urge everyone to continue to behave responsibly and remember ‘hands, face, space and fresh air’ to suppress COVID as we push on with our vaccination programme."
In England, pubs and restaurants have been making changes during lockdown to maximise their ability to serve customers outside.
But the British Beer and Pub Association estimates that just 40% of licensed premises have the space to reopen for outdoor service.
The previous 10pm curfew rule and the requirement to order a substantial meal with a drink have been scrapped, but social distancing must be observed.
Jake Greaves, landlord of The Shortlands Tavern in Bromley is looking forward to seeing his customers again but says it is the indoors life of the pub that he misses most.
He told Sky News: "For us to feel like things are truly back to normal is for people to be back at the bar again and ordering drinks. We’re a pub at the end of the day, and table service – it’s nice from a customer point of view, but for operating as a pub – is very difficult. It’s not what we’re used to at all really."
Domestic holidays can resume to an extent, with overnight stays permitted in self-contained accommodation, such as holiday lets and campsites where indoor facilities are not shared.
But these can only be used by members of the same household or support bubble.
International holidays remain banned until an unknown date, amid a row over the cost of testing.
People are not be allowed to visit each other’s homes, with socialising indoors still prohibited outside support bubbles.
It is the third in a series of easings since the third national lockdown was legally imposed in England on 6 January.
The next significant date is 17 May, when socialising indoors will be permitted under the "rule of six" – if the prime minister judges that the vaccination programme is safely breaking the link between infections and deaths.
Meanwhile, Wales is also enjoying renewed freedoms from today, with non-essential retail reopening and border restrictions eased to permit travel again with the rest of the UK and Ireland.
Remaining school pupils return to face-to-face teaching in Wales and Northern Ireland, in moves being echoed in Scotland as pupils return from their Easter breaks.
The "stay at home" order in Northern Ireland also ends as the number of people permitted to meet outdoors rises from six to 10.
Professor Peter Horby, chairman of the New and Emerging Respiratory Virus Threats Advisory Group, told Times Radio: "The watchword has got to be caution, really.
"It’s not clear exactly when or how big it will be, but there is, I think, inevitably going to be a bit of a rebound in the number of cases when things are relaxed."
The Oxford University academic said the vaccination programme will minimise hospital admissions and deaths but warned it will not be completely effective.
"I think we can be joyful and enjoy the freedoms but we’ve still got to realise there’s still a large number of people who’ve not been infected or vaccinated and so they will be at risk."
After three months of full national lockdown, the government said on Sunday that a further seven people had died in the UK within 28 days of a positive COVID-19 test.
Around 61% of adults have received at least one dose of the vaccine, according to official figures suggesting that more than 32 million people have received a jab. More than 14% have had both doses.