Boris Johnson has announced a new tier 4 of coronavirus restrictions to cover London, the east of England and areas of the southeast after the current tier 3 restrictions were considered insufficient for slowing the spread of a mutant strain of the coronavirus.

The new tier will include restrictions on travel affecting people living in the restricted areas and anyone looking to enter them.

The new rules will order people in tier 4 areas to stay at home by law. The rules will cover, Kent, Buckinghamshire, the east of England, all 32 London boroughs and the City of London.

Exemptions will be in place to allow people to travel for healthcare, education or childcare.

Outdoor exercise will be permitted and people will be permitted to meet with only one other person in a public space outside, unless they are part of a support bubble.

The government will advise people not to enter tier 4 areas. Earlier advice for entering tier 3 areas from lower areas had permitted travel for “necessary reasons”.

These included work, education, youth services, to receive medical treatment, or because of caring responsibilities.

The Christmas bubble policy will not apply in tier 4, meaning that separate households cannot mix even on Christmas Day. Support bubbles will still be permitted for people at particular risk of loneliness.

Elsewhere, bubbles will still be allowed for Christmas Day only, not for the previously scheduled five-day period.