People between 50 and 70 could be given personalised risk ratings, taking into account factors like age and medical history.
Millions of over 50s could be told to stay at home under a “nuclear” option to prevent a new nationwide lockdown if there is a second wave of coronavirus.
Boris Johnson is reportedly considering asking a greater number of people in England to take part in the shielding programme should there be a big spike in COVID-19 cases.
A Sunday Times report said people aged between 50 and 70 could be given personalised risk ratings, taking into account factors such as age and medical conditions.
2.2 million were deemed most vulnerable and asked to shield themselves from society during the spring peak of the virus – advice that ended on Saturday.
As part of a strategy to tackle a potential second wave of coronavirus in the future, the prime minister is also reportedly considering lockdown conditions for London.
Ideas include giving Londoners stay-at-home orders, restricting travel beyond the M25, and banning people from staying in other people’s homes, similar to policies implemented in local lockdowns imposed in Leicester and parts of the north-west of England.
Measures to prevent a second nationwide lockdown, and any economic fallout, were discussed by Mr Johnson at what was described by sources as a “war game” session with Chancellor Rishi Sunak on Wednesday.
Downing Street distanced itself from the details in the reports, calling them “speculative”.
Housing Secretary Robert Jenrick said: “We don’t have any plans to (advise over 50s to shield).
“Moving forwards, we hope to be able to operate on a localised approach… but we don’t have any plans for a national blanket approach.”
It comes after the prime minister was forced to postpone the latest easing of lockdown on Friday.
The planned reopening of some businesses in the leisure and beauty sectors was delayed due to fears that the prevalence of coronavirus was rising for the first time since May.
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Experts have already suggested that pubs could be closed in exchange for allowing schools to reopen fully in September.
It follows a warning from England’s chief medical officer Professor Chris Whitty that the country was “near the limit” of how many parts of normal life could be resumed safely.
It has been less than a month since pubs were allowed to reopen after the peak of the virus, but Professor Graham Medley, a member of the Scientific Advisory Group for Emergencies, said the “trade off” could be required for the sake of children’s education.
Most schools closed at the end of March as the UK went into lockdown, although many remained open for children of key workers and vulnerable pupils.
More than half of pupils struggled to learn at home during lockdown, according to an Office for National Statistics survey, raising concerns about the continued closure of schools.
The government said that eight more people had died with coronavirus in the UK in the 24 hours to 5pm on Sunday, bringing the total to 46,201.
In the 24 hours to 9am on Sunday 744 more cases had been confirmed, bringing the UK total to 304,695.