Some schools can reopen and groups of six people will be able to meet outside as all five tests to lift the lockdown in England have been met.
He also confirmed primary schools and nurseries can reopen from Monday, and from 15 June, some secondary school pupils will be able to return to provide “some face to face contact time” for years 10 and 12.
Outdoor retail and car showrooms can also open from Monday, and up to six people, of all ages, will be able to meet outside as long as those from different households remain two metres apart.
“These changes mean that friends and family can start to meet their loved ones, perhaps seeing both parents at once or grandparents at once,” Mr Johnson said.
However, he said people should not be making overnight stays in other households.
The prime minister suggested that barbecues are allowed as long as everyone stays socially distanced and washes their hands and uses “common sense”.
He repeated that people should not be travelling across the country to stay overnight and urged people to avoid “seeing too many people from too many households” in quick succession, but said further guidance would follow.
He also said those who were shielding for health reasons should continue to do so.
Mr Johnson also explained how his five tests for easing the lockdown had been met.
He said the “heroic efforts” of NHS workers and the public mean that the first test of protecting the NHS’s ability to cope has been met, with 475 admissions in COVID-19 in England on 26 May.
He also said the second test – a sustained and consistent fall in the daily death rates from COVID-19 – has also been met.
The government is also satisfied that the third test has been met since the rate of infection is decreasing, with an average of 2,312 new cases being confirmed in the last seven days.
On the fourth test – combating challenges over the supply of PPE and testing – Mr Johnson ran through a series of recent government action and said this has also been met.
The fifth test is that any adjustments to the lockdown won’t risk a second peak of infections that overwhelms the NHS.
Non-essential retail will also be allowed to open from the middle of next month if the five tests are still being met.
The prime minister said that different parts of the UK are moving at different speeds.
He said: “I cannot and will not throw away all the gains we’ve made together and so the changes we’re making are limited and cautious.
“It’s thanks to the caution you’ve shown so far that all five met are being met.
“The result is that we can move forward with adjusting the lockdown in England on Monday.”
Earlier, Scotland’s First Minister Nicola Sturgeon said people in Scotland will be allowed to meet outdoors in groups of up to eight from tomorrow.
Mr Johnson also told the Downing Street briefing that people who lose income as a result of local lockdowns “will be helped”.
Answering a question by Carol from Sunderland about what compensation would be offered to those who can’t go to work, he said the government will do “all we can” and that the furlough scheme will stay in place.
He also said he wants to avoid too many local outbreaks, saying this is why it’s “vital” people follow the measures.
The government’s chief scientific adviser, Sir Patrick Vallance, told the briefing that the rate of infection has fallen to 0.7-0.9. Last week, it was 0.7-1.
The R rate has gone down
It is now 0.7-0.9
Last Friday it was 0.7-1
— Sam Coates Sky (@SamCoatesSky) May 28, 2020
However, he advised that things need to be done cautiously.
He said: “We are still seeing new infections every day at quite a significant rate and the R is close to one.
“That means there is not a lot of room to do things and things need to be done cautiously, step-by-step and monitored and the test and trace system needs to be effective in order to manage that.”
Mr Johnson announced that 37,837 people have now died with coronavirus – an increase of 377 deaths since yesterday.
Next week from Monday to Thursday, Dermot Murnaghan will be hosting After the Pandemic: Our New World – a series of special live programmes about what our world will be like once the pandemic is over.
We’ll be joined by some of the biggest names from the worlds of culture, politics, economics, science and technology. And you can take part too.
If you’d like to be in our virtual audience – from your own home – and put questions to the experts, email [email protected]