The Prime Minister insisted the lockdown is not over yet, however, and said it would be "madness” to “throw away” the progress made so far and allow a second peak of infections.
"This is not the time simply to end the lockdown this week," he said.
"Instead we are taking the first careful steps to modify our measures."
People in England will be encouraged “to take more and even unlimited amounts of outdoor exercise” from Wednesday, Mr Johnson said.
He added: "You can sit in the sun in your local park, you can drive to other destinations, you can even play sports but only with members of your own household."
Those who can’t work from home will also be encouraged to go to work from Monday but commuters should avoid public transport, Mr Johnson said.
He said: “When you do go to work, if possible do so by car or even better by walking or bicycle. But just as with workplaces, public transport operators will also be following COVID-secure standards.”
Capacity on public transport will be limited, the Prime Minister said.
Guidance for employers to help make workplaces "Covid secure" will be set out by the Government, who will also increase fines for anyone caught breaching the lockdown rules which have been in place since 23 March.