Covid restrictions could be needed if infections continue to soar after yesterday’s highest daily total since July.

The 49,156 new cases raised the spectre of indoor face masks, Covid passports becoming mandatory at large events and working from home rules returning.

The measures are a part of Boris Johnson’s Plan B, which the government has ruled out introducing imminently.

But he admitted the winter months ahead will be ‘challenging’.

Scientists also expressed concerns about the slow rollout of booster jabs after projections that immunity against the virus may be waning.

Plan A puts the vaccination drive as the first line of defence, with the prime minister saying unvaccinated Brits are up to nine times more likely to die, depending on their age, than if they have had both jabs.

The PM’s official spokesman said: ‘There is absolutely no plan to introduce Plan B currently. We retain that capability if required if we believe the NHS is coming under unsustainable pressure.

‘We obviously keep very close watch on the latest statistics. We always knew the coming months would be challenging.’ 

Analysis shows only 3.7 million of the 8.5 million people deemed clinically vulnerable who were double jabbed more than six months ago have received a booster.

It leaves more than half of them (4.8 million) with potentially weakened immunity against coronavirus.

As many as 22 million people will be ready for their third jab by mid-December, but on the current trajectory some will be waiting until the end of January for theirs.

John Roberts of the Covid-19 Actuaries Response Group told the Telegraph: ‘At the start of the booster campaign, the Secretary of State for Health and Social Care stated that the aim was to protect the most vulnerable from Covid-19 as we head into the autumn and winter months.

‘But at the current rate, it’s likely to be towards the end of January before the approximately 22 million that fall into the most vulnerable groups receive the booster.

‘With case numbers very high and still rising, and admissions to hospital also rising again, it’s clear that accelerating the booster rollout is vital to reduce the pressure on health services and minimise Covid-related deaths this autumn and winter.’

MORE : Everything we know about Boris Johnson’s Covid winter plan

MORE : UK records nearly 50,000 new Covid cases as expert warns immunity is waning

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