England has gone back into a national lockdown as COVID-19 cases and deaths increase rapidly.
Boris Johnson put science and data at the forefront of his lockdown announcement on Monday in an attempt to impress on the public the need to stay at home and comply with tougher measures - which he blamed on the new, more transmissible variant of the virus.
One of the main factors the government and its advisers looked at to make the decision was the number of people in hospital.
Sky News has dug deeper to look at how many people with COVID-19 are in hospital beds, how old those people are and how many people have COVID-19 from each age group in England.
The number of beds occupied by COVID-19 patients has risen steeply since the middle of December, two weeks after a small decrease following the end of the November lockdown.
Compared with the summer, where there was a decrease in bed occupancy after the first lockdown, the data shows numbers have been steadily rising since mid-September ahead of the steep rise in December.
Virologist Dr Stephen Griffin, associate professor at the school of medicine, University of Leeds, said the data means the government needs to take a different approach to lifting lockdowns.
He told Sky News: "You can see from the graphs, the increase has its roots in the end of summer and autumn.
"The figures started to come up in September - there's a two week lag between getting infected then being admitted to hospital, that's all starting in August.
"The low point was in July but then we unlocked and Boris Johnson was telling everyone to go back to work, eat out to help out - that's inconsistent with helping to stop cases, and therefore hospital admissions then deaths, from rising.
"Just locking down isn't the strategy, it's what you do either side of that lockdown and during that counts.
"You need to keep cases low after lockdown and maintain some restrictions to ensure cases don't bounce back."
Another measure of how the country is doing is how many COVID-19 patients are in mechanical ventilator beds, which are a last resort for patients who are unable to breathe by themselves.
They are now used much less than during the spring peak as other treatments such as dexamethasone mean patients do not have to be placed on ventilators.
But, since mid-December, there has been a steep rise in their use.
The nature of the virus, as has been seen since March, is that older people are more likely to be admitted to hospital, and more likely to be placed on a ventilator, which means they are more likely to die as they are in a very serious condition by that point.
Cases are by far the highest in those aged 90 and older but are rising in the teenage, young and middle-age groups.
The percentage of positive tests recently has been highest among secondary age children, according to the latest data from the COVID-19 Infection Survey by the Office for National Statistics (ONS).
Positive tests in the week ending 12 December increased in all age groups, apart from in school year 12 to 24 years old, and those aged 50 to 69 - which both stayed at a similar, but high rate, as the previous week.
By the end of the November lockdown, the latest data available shows hospital admission rates were soaring in those aged 85 and over, while deaths the week before were high in people over the age of 74.
Dr Griffin added that while testing is "fantastic", tracing contacts of those with COVID-19 has not been and that, combined with people going on summer holidays, then going back indoors as it got colder, helped to increase cases, which translates to more hospital admissions and then deaths.
Downing Street has said the new variant, which is more transmissible, is to blame for the "rapidly escalating case numbers".
However, Dr Griffin said that is not the sole reason why cases have risen so much recently.
"The variant was only centred around Kent and parts of London in September, and yes, the speed that it's exploded at is scary," he said.
"But, the rise in October and November was due to the other variant, which this new one has replaced.
"That older variant was the reason for the lockdown in November - which SAGE advised should happen in September because they could see cases rising then.
"The fact is, they did not do enough during that circuit breaker to stop cases rising after and the tiers that were then introduced weren't stringent enough.
"The attitude appears to be what they can get away with to get R [the number of people one person transmits COVID-19 to] below 1, but that's not everything and they haven't managed that for a long time now."
Although cases and deaths are rising, Mr Johnson has placed much hope on vaccinating people to be able to lighten restrictions.
He has set a target of administering the COVID-19 jab to nearly 14m people in the top four priority groups by the middle of February, with the lockdown to be reviewed on 15 February.
Dr Griffin warned that may not be enough time to stop cases and deaths rising again after, especially with lags in people being admitted to hospital after feeling ill, then further time before some die in hospital.