How and when will Blackburn come out of national lockdown?

His comments come as England entered its third national lockdown with stringent new controls, including closing schools to most pupils, in an attempt to prevent the NHS being overwhelmed by a surge in new infections.

Here we look at how the country is going to come out of lockdown.

– Why has another lockdown been introduced?

In a televised address on Monday evening Prime Minister Boris Johnson said hospitals were under more pressure than at any time since the start of the pandemic, with the number of Covid-19 patients in hospital in England rising by nearly a third in the last week to 27,000.

Mr Johnson said that with record cases across the UK and deaths up by 20% over the last week, England needed to enter a new national lockdown.

– How fast is the virus spreading?

The latest figures showed a further 407 people have died within 28 days of testing positive for Covid-19 as of Monday, and there were a record 58,784 more lab-confirmed cases of coronavirus in the UK.

Of the 315 local areas in England, 292 (93%) have seen a rise in case rates during the seven days to December 31 compared with the previous week, 22 (7%) saw a fall, and one was unchanged.

– How long will the new lockdown last?

It is not clear yet how long the lockdown will last, but the Prime Minister said the prospect of the vaccination programme being rolled out across the country could enable restrictions to be progressively eased from mid-February.

But in a round of broadcast interviews on Tuesday, Mr Gove said relaxation of the rules may have to wait until the following month – and that even then some measures may have to remain in place.

Mr Gove also said that the restrictions will be kept “constantly under review”.

– At what stage is the vaccine-rollout?

More than a million people have received their first coronavirus vaccination, with the first Oxford/AstraZeneca jabs being rolled out on Monday.

Mr Johnson said that “with a fair wind in our sails” it should be possible to vaccinate 13 million of the most vulnerable people by mid-February, paving the way for controls to be eased.

Top of the priority list are people who live and work in care homes, followed by people over the age of 80 and frontline health and social care workers, including NHS staff.

Next on the list are people over the age of 75, and the fourth group are people aged 70 and those classed as clinically extremely vulnerable.

– How likely is this target to be hit?

Mr Gove said the NHS was working “24/7” to ensure 13 million people are vaccinated by the middle of February.

Professor Nilay Shah, at Imperial College London, said that with a great deal of co-ordination of manufacturing, logistics, rapid training of vaccination administration personnel and co-operation of patients, it should be possible to reach daily vaccination levels of 300,000 to 500,000 doses per day.

But this depended on everything going right every day, he added.

Prof Shah added: “If we take the top four groups, this would be very approximately 10 million people. Assuming that we will go for a prime and boost vaccination strategy, even if the gap may be longer, that implies 20 million vaccinations.

“At 400,000 doses per day, assuming we move to seven-days-a-week operation, that is 50 days which would get us to mid-Feb (for 100% coverage).

“If the aim is for the first dose for the top four priority groups by mid-February, then we would need to hit 200,000 doses a day, again this is achievable but everything needs to go right every single day.”

Mr Johnson also said that the limiting factor in expanding the UK’s vaccine rollout was not supply or staff, but waiting for batches to be approved and quality controlled.

– Are there other factors involved in deciding whether the lockdown can be lifted?

Throughout the pandemic there have been a whole host of factors used to decide whether to impose or relax restrictions.

One of the key ones has been the virus’ reproductive number, or R value, which is the rate the virus is spreading. If the R number is above one it means the infection is growing.

Sage member Professor Calum Semple said the R-rate on the downslope was not a very useful indicator and what needed to come down were case numbers presenting to hospital and levels of sickness within the community.

He added: “It’s both the absolute numbers in the community and the hospitals that will predict when we’re coming out of higher degrees of regulation.”

Other factors which have previously been considered include case rates, rates in the over-60s, the positivity rate – the number of positive cases detected as a percentage of tests taken – and the pressure on the NHS.

It is not clear which of these factors, or any others, will also be considered when the Government comes to decide whether to ease restrictions.

– So we could be in for the long haul?

Mr Johnson said that even if the vaccination target is hit there remained a time lag of two to three weeks from getting the jab to receiving immunity, while there will also be a further time lag before the pressure on the NHS is lifted.

Professor Mark Woolhouse, a member of the Government’s Scientific Pandemic Influenza Group on Modelling (SPI-M), said the exit was likely to be “slow and cautious”.

The professor of infectious disease epidemiology at the University of Edinburgh also warned that vaccinating priority groups was not enough to achieve herd immunity.

He added: “The PM gave an ambitious target for vaccine rollout for priority groups by mid-February.

“Vaccinating groups will protect them from infection and disease. However, it will not be enough to achieve herd immunity so the virus would still be able to circulate in the general population in the absence of restrictions.”