The end of the second national lockdown on December 2 will see the introduction of a tougher tier system in England, with 99% of the country to be placed in the top two tiers of restrictions.

But when will the restrictions be reviewed and what will be considered when deciding an area’s tier?

– How many people are to face tough restrictions?

More than 55 million people will be placed into Tier 2 and Tier 3 measures on December 2, meaning mixing between households indoors will effectively be banned for the vast majority of the country.

Only the Isle of Wight, Cornwall and the Isles of Scilly – accounting for little more than 1% of England’s population – face the lightest Tier 1 coronavirus restrictions.

Large swathes of the Midlands, North East and North West are in the most restrictive Tier 3, which accounts for 41.5% of the population, or 23.3 million people.

The majority of authorities – including London – will be in Tier 2, which will cover 57.3% of the country, or 32 million people.

– What are the key indicators that will primarily determine the restrictions in each area?

Five factors are considered:
– case detection rates in all age groups;
– case detection rates in the over-60s;
– the rate at which cases are rising or falling;
– the positivity rate – the number of positive cases detected as a percentage of tests taken;
– and pressure on the NHS, including current and projected occupancy.

Downing Street has declined to give any further details on the indicators, nor any estimate of the thresholds.

– Why are there not rigid thresholds?

The Government has said it needs to maintain flexibility to weigh the indicators against each other – such as whether hospital capacity in neighbouring areas is lower.

Another example given in the Coronavirus Winter Plan is that case detection rates would need to be weighed against whether the spread of the virus is localised to particular communities.

The plan states “given these sensitivities, it is not possible to set rigid thresholds for these indicators, as doing so would result in poorer quality decisions”.

– When can any changes be made to the tier system?

The first review of the tiers is set for December 16.

Prime Minister Boris Johnson told a Downing Street briefing the allocation of tiers will be reviewed every 14 days from that date, and suggested mass testing could make households exempt from restrictions.

He said: “Now testing on this scale is untried, but in due course, if it works, where people test negative it may also be possible for families and communities to be released from certain restrictions even if their home area stays in Tier 3.”

Former minister Tobias Ellwood said the Government should be using up-to-date data to make its decisions on the new restrictions. He noted the information used to place different areas into a tier would be more than a week old by the time they are imposed.

He also called for the criteria and justification for the tier system to be outlined so that people can “better understand” what is needed to get out of a tougher tier.

He told BBC Breakfast on Friday: “I think that clarity of communication is so important at this time.”

– What are the chances of regions moving out of a tough restriction tier by Christmas?

Communities Secretary Robert Jenrick insists there is “every reason” to expect some areas could be moved into a lower tier on December 16.

He said the Government, advised by the experts, would look at each local authority area and see whether there is potential for movement.

He told Sky News: “There were a number of places which were quite finely balanced judgments where they were on the cusp of different tiers. Those are the places that are more likely to be in that position.”

In contrast, Professor John Edmunds, a member of the Government’s Scientific Advisory Group for Emergencies (Sage), warned “that is quite an early time to be able to see what the effect has been”.

He told BBC Radio 4’s Today programme: “I can’t imagine there will be huge changes at that point, just simply because I don’t think we will have accumulated much data by then.”