“That means following the two metres or one-metre-plus guidance and regular hand-washing,” said the PM’s spokesman.

Downing Street there did not have to be a gap between when you see another household. You could meet with one household in the morning and another one in the evening.

However, only households that are in a “support bubble” can have physical contact with each other.

Downing Street said: “Where two households meet indoors we’ll be asking people to follow our advice which means to remain socially distant, regular hand washing and cleaning shared spaces.

“I think people will show common sense and they’ve worked really hard to get this disease under control and I think they will understand that we still have more to do. The virus is not beaten.”

Downing Street said the advice would allow people much more social contact, allow people to see both sets of grandparents and have people over for dinner.

The changes clear the way for Britons to start booking summer holidays — and for a rescue of London’s shattered hospitality sector that has been in deep freeze since March.

In place of the blanket two-metre rule of social distancing, there will also be a “one metre plus mitigation” for situations where two metres are not possible. Mitigation could mean wearing a mask, such as on public transport, or keeping the encounter brief.

The Prime Minister told the Commons that the pandemic had left “permanent scars” and he would not hesitate to lock down again if necessary.

“At every stage caution will be our watchword. Every stage will be conditional and reversible.”

We cannot life all the restrictions at once so we have to make difficult judgments,” he told MPs.

“The more we open up, the more vigilant we will need to be.