What could a 'road map' out of Covid restrictions look like?
Pressure is building on the Prime Minister to outline how areas with the strictest Covid restrictions can return to some notion of normality.
More than 50 Conservative backbench MPs have written to Boris Johnson calling for a "clear road map" out of lockdown measures in northern England.
In a letter, the group representing northern constituencies warned the pandemic is threatening the PM's election pledge to "level-up" the country.
So what could a route out of lockdown actually look like?
What are Tier 3 restrictions?
Mr Johnson announced the three-tier strategy earlier this month, which splits different areas of England into medium, high and very high alert levels.
The highest alert, tier 3, bans social mixing both indoors and in private gardens, while bars and pubs are told to close unless they can operate as a restaurant.
Local leaders will help to determine whether other venues should be closed, such as gyms or casinos, in very high alert level areas.
Covid tiers: - What are the differences between each alert level in England?
Medium (Tier 1) - Rule of six applies indoors and outdoors. Pubs and restaurants close at 10pm.
High (Tier 2) - Households must not mix indoors in any setting including pubs and restaurants. Rule of six applies outdoors
Very high (Tier 3) - Households must not mix indoors, or in private gardens. Rule of six applies in outdoor spaces including parks. Pubs and bars which don't serve meals will be closed
Which areas are affected by the top-level restrictions?
More than eight million people in England, predominantly in the North, will be under the most stringent Covid-19 restrictions by the end of October.
A total of 39 local authorities areas have been placed into the toughest tier including the Liverpool city region, Greater Manchester, South Yorkshire and Lancashire.
What have northern MPs called for?
The North-South divide in the tier system has sparked concern among Tory MPs - the newly formed Northern Research Group has written to the PM to express its fears.
The group, led by former northern powerhouse minister Jake Berry, urged Mr Johnson to set out a "clear road map" out of lockdown restrictions.
In the letter, seen by the PA news agency, Mr Berry said the MPs have concerns the cost of the pandemic will be paid for by the "downgrading of the levelling-up agenda, and northern constituencies like ours will be left behind".
Why is this a concern for Tories?
Mr Johnson won a majority of 80 seats at last year's general election, turning many traditional Labour constituencies – which formed the so-called Red Wall – blue.
Some MPs have expressed concern these newly won seats could be returned to Labour at the next election if the government fails to deliver on its promise to "level up" the country.
Indeed a poll by ITV News recently found 67% of people in northern England are not confident the government will deliver on its "levelling up" promise.
So what is it northern MPs want?
In the letter, Mr Berry calls for a "clear road map down the tiering system and out of lockdown", prioritising the acceleration of "key road, rail and social infrastructure" projects, and developing an economic recovery plan for the North.
What kind of infrastructure projects could this include?
In the letter, Mr Berry highlighted the Trans-Pennine HS2 Northern Powerhouse Rail project, strategic development corridors and ultrafast broadband.
Northern Powerhouse Rail is a scheme to develop high-speed links across the Pennines, while strategic development corridors are areas where improving transport links will boost economic growth.
Is there a set of criteria for a region moving up or down a tier?
There is no published criteria on what factors lead to an area being moved from one tier to another.
But Dr Clare Gardiner, director general of the Joint Biosecurity Centre (JBC), said there is a "basket of indicators" looked at with the chief medical officer, who then makes recommendations to ministers.
Do we know what factors are considered?
Dr Gardiner outlined a range of indicators for a region moving up to Tier 3 - including having a rate of more than 100 to 150 coronavirus cases a week per 100,000 population.
Other factors include case rates in the over 60s, having a positivity rate of more than 7.5% and the number of people being admitted to hospital.
But she said the same criteria could not be used to take an area out of the highest tier because there is very little chance they can meet it in the four-week review period.
Dr Gardiner said: "I think it would be important to see a stabilisation of case rates, ideally before coming out of a tier."
How are the decisions going to be made?
Dr Gardiner said the decision to move an area out of the top tier will come after discussions between public health officials and local leaders.
She added: "There’s a lot of professional judgment that needs to be brought to bear, looking at those key indicators and trying to understand if there is a stabilisation or slowing of growth so that NHS colleagues are feeling more comfortable about their ability to retain key services."
How long will it take to know if the tier system is working?
Dr Gardiner said it will take two to three weeks to establish whether tough top-tier coronavirus restrictions are working in a region.
She said part of the lag comes from the virus having a 10-day incubation period.
But a recent survey has suggested more than a third of doctors in England feel the government’s tiering system will have no impact on efforts to contain the spread of coronavirus.
What has the government's response been?
Business Minister Nadhim Zahawi said Tier 3 areas are subject to 28-day reviews and bringing the virus under control is the route out of restrictions.
He also defended the government’s support for the North and Midlands, and said Tory MPs who have written to Boris Johnson are "champions for their area".