Vulnerable workers such as taxi drivers, hauliers and hospitality staff could be encouraged to come forward first in their groups. But experts fear complicating the simple age-based priority list will make it difficult to coordinate and slow down shots. Based on current rates, the 35-39 age group can expect to be invited to book an appointment in the second half of May.
Those aged 30-35 could be called in by late May or early June. Anyone aged 25-29 and 18-24 would be contacted in the rest of June and July.
Up until now the rollout has concentrated on offering over-50s jabs.
More people under 65 are now being admitted to hospital with Covid-19 than older age groups as vaccination protection kicks in.
NHS England statistics show that on average, 51 percent of virus patients hospitalised daily were under 65 and 49 percent over.
This is down from two thirds being aged over 65 at the peak of the second wave in January.
However, there are growing concerns that those travelling overseas could bring dangerous coronavirus variants into the UK which are more resistant to vaccines.
Government adviser Prof Peter Openshaw warned that lockdown could be reimposed if new variants get out of control.
It came as Britain’s biggest surge testing operation is underway to tackle an outbreak of the South African variant in London.
The flare-up started when a man flew in to the UK from Africa in February and it has since spread to a care home and two schools.
According to documents seen by the BBC the country he travelled from was not on the red list for mandatory hotel quarantine at that time, but is now.
Prof Openshaw, a member of the Covid-19 clinical information network, said: “This is not good news.
“If we get rapid spread of the South African or other more resistant variants, it may well be that we are going to have to put the reductions of lockdown into reverse.”
Thousands of residents queued for up to two hours for PCR tests at sites in two south London boroughs.
A million people aged over 11 who live, work or travel through Wandsworth, Lambeth or Southwark are being encouraged to get checked.
And people living in an area of Barnet have also been urged to get a test after a case of the South African variant was found there. Officials will go door-to-door in the N3 postcode to deliver PCR test kits and a mobile unit will be set up at Finchley Central Station.
There have been 533 confirmed cases of the South African variant in the UK and 11 more probable cases, according to Government figures.
Lockdown was eased throughout England on Monday, with nonessential retail and pub beer gardens permitted to open.
Prime Minister Boris Johnson said he has no plans to change the roadmap out of lockdown. The next “waymarks” on England’s plan to ease restrictions are due on May 17 and June 21.