Up to six people will be allowed to meet outside "as long as they respect social distancing rules," in gardens and other private outdoor spaces, he said.
"At the moment, as you know, people can meet in parks but not in private gardens -- this was a cautious first step -- but we know that there is no difference in the health risk," he added.
However, people from different households should still not meet inside homes.
From Monday, they will be permitted to meet outside, he said -- "provided those from different households continue strictly to observe social distancing rules by staying two metres apart."
To the relief of many British parents, schools will reopen to more children, starting with nurseries, pre-school, kindergarten and some grades in elementary schools.