The Scientific Advisory Group for Emergencies (SAGE) said that means that on average every 10 people infected will infect between 9 and 10 other people.
The R peaked in early October at between 1.3–1.6 before falling back down.
The growth rate has also been revised to between -2 percent to 0 percent, meaning the number of new infections is shrinking by up to 2 percent every day.
A three-tiered lockdown system was implemented in England from Oct. 14, and a four-week full national lockdown started on Nov. 5.
The R—the average number of secondary infections produced by a single infected person—had been one of the main criteria, along with number of cases, that the UK government used to decide where and when to impose restrictions until now.
A new, tougher tiered system will be implemented from Dec. 2, if Parliament passes it on Tuesday.
The government now considers five criteria when deciding which areas go into which tiers: public health recommendations informed by case detection rate, how quickly case rates are rising or falling, positivity in the general population, current and projected (3–4 weeks) pressure on the NHS, and local context.
The pressure on the NHS is normally higher in winter due to seasonal flu. This may have contributed to why many more areas in England are to be placed into higher tiers when the four-week national lockdown ends than they were before, and places with low case numbers will also be put into higher tiers.
The government also said the restrictions will be tougher because evidence showed that the previous tiers didn’t work to reduce CCP (Chinese Communist Party) virus infections.
However, data published on Thursday by the Office for National Statistics indicated that according to estimates from a weekly swab-sample survey, infections in England were already dropping in the second week of the national lockdown.
The results are consistent with other data that suggests the so-called second wave of the CCP virus was already fading before Nov. 5, when the lockdown was enforced.
The different data analyses have fuelled the growing rebellion against future lockdowns among Conservative Party members.
Several senior Tory members, along with a 70-member strong Parliamentary COVID Recovery Group, have demanded the government publish a full cost-benefit analysis of the proposed restrictions on a regional basis.
It is unclear if Parliament will pass the new tiers plan, with Labour’s Shadow Health Minister Justin Madders saying on Friday the party was yet to decide on its stance.
Simon Veazey contributed to this report.