The measures will be imposed across England and will replace the current and only recently introduced three-tier ‘traffic light’ system.
Mr Johnson had previously said that a short, sharp lockdown or “circuit breaker” as recommended by scientific advisers and such as the kind imposed in Wales, would not be necessary. Instead, three tiers of local measures were introduced nationwide.
The U-turn to a second national lockdown comes after scientific forecasting that suggests the winter death toll could surpass the 85,000 mark that had been predicted by government modelling in a worst-case scenario.
Mr Johnson said, “our hope was that by strong local action, strong local leadership, we could get the rates of infection down where the disease was surging”, but that “the virus has been spreading even faster than the reasonable worst-case scenario of our scientific advisers”.
Mr Whitty said that “the prevalence of this disease has been going up extremely rapidly over the last few weeks, having been very flat over spring and summer”, with daily cases of coronavirus averaging around 50,000.
The new measures will enforce the closure of much of the hospitality industry, including pubs and restaurants, however takeaways and deliveries will be permitted.
Essential shops, such as supermarkets, and educational settings, including nurseries, schools and universities, will remain open. Outdoor exercise will be allowed, while foreign travel will be banned.
The measures will remain in place until 2 December.
Here’s everything we know so far about what people can and cannot do in light of the new guidance.
Visiting friends and family
The new rules will mean there will be no mixing of people inside homes anywhere in the country, except for in cases where childcare and other forms of support are necessary.
However, under the new lockdown, unlike the first, You can exercise or visit outdoor public places with the people you live with, your support bubble, or 1 person from another household.
Outdoor public places include, parks, beaches, countryside, public gardens, allotments and playgrounds. You cannot meet in a private garden.
Single-adult households will still be permitted to form or maintain a support bubble with another household.
If you are clinically vulnerable or over the age of 60, the prime minister said you must minimise contact with other people as much as possible.
Schools and universities
There will be another key difference between this and the first national lockdown: schools, colleges and universities will be allowed to stay open.
In March, only vulnerable pupils and children of key workers were permitted to attend school in person, with A-levels and GCSE exams being cancelled nationwide.
Pubs and restaurants and entertainment venues
Establishments will be permitted to open to offer takeaway food and drink.
Non-essential shops will also close for the duration of the second lockdown.
However, this does not include supermarkets, which will also not be required to follow the Welsh example of fencing off non-essential goods, such as clothes.
Travel within the UK will also be discouraged, except for work, while overnight stays away from home will only be allowed for work purposes.
Exercise and outdoor sport
Just like the first lockdown, outdoor exercise will be allowed and encouraged, with people permitted to meet up with one other person from a different household for walks and exercise.
While travel within the UK is discouraged, people are allowed to do so for work purposes.
The new rules mean that people are expected to work from home if they can do so, with the government also advising people to avoid taking public transport if at all possible, not just because services are currently limited, but because doing so will make it easier for you to maintain social distancing.
Industries such as manufacturing and construction will be encouraged to keep running.
All religious services are to be stopped once more under the new guidelines. However, private prayer can continue.