BORIS Johnson has been warned vaccination alone will not be enough to bring down Covid infection rates as experts urge Downing Street to reintroduce tougher restrictions.

The UK is now among the world’s worst coronavirus hotspots, both in terms of infections and deaths.

But the Prime Minister has resisted pleas from health leaders for tighter rules in England despite the rising number of cases, and has said vaccines will get the country through the winter and out of the pandemic.

Professor Adam Finn, who is on the Joint Committee of Vaccination and Immunisation (JCVI), warned against complacency in what he described as a "worsening" situation.

He said people in England need to be testing themselves, wearing masks and avoiding crowds in enclosed spaces in order to prevent "a real meltdown".

His comments came after another prominent adviser to the Government on Covid-19 said he is "very fearful" there will be another "lockdown Christmas" as he urged the public to do everything possible to reduce transmission of the virus.

READ MORE: Scotland 'faces a four-fold Covid spike at COP26 in a best-case scenario'

Professor Peter Openshaw, a member of the New and Emerging Respiratory Virus Threats Advisory Group (Nervtag), warned case numbers and death rates are currently "unacceptable".

He said measures such as working from home and mask-wearing are "so important" as part of efforts to control the spread of Covid.

In Scotland, face masks are still required when moving around in indoor venues such as bars, nightclubs and restaurants and on public transport – even if you have been double vaccinated.

Openshaw also advised people in England to "take matters into your own hands", telling BBC Breakfast on Saturday: "Don't wait necessarily for Government policy."

Meanwhile, Dr Katherine Henderson, president of the Royal College of Emergency Medicine, said people need to try to minimise the need for healthcare resources.

She told Sky News's Trevor Phillips On Sunday: "We didn't go into the pandemic in a great place in emergency care. We didn't have enough beds then.

The National: Tory Health Secretary Sajid Javid has warned cases could rise to 100,000 a dayTory Health Secretary Sajid Javid has warned cases could rise to 100,000 a day

"The problem is that things are worse at the moment so we need everybody to be as careful with the healthcare resources as they possibly can be, and try and minimise the need for healthcare resources.

"So if we've got 8000 patients in hospital who are suffering Covid, if we didn't have those patients that would be another 8000 beds in the system.

"So every bed that gets filled by a patient with Covid in a sense is in a hospital bed with a potentially avoidable disease, and that's what we need people to focus on if we want to get through the elective backlog."

Tory Health Secretary Sajid Javid announced this week that new cases could reach 100,000 a day, but Downing Street insists there is still spare capacity in the NHS and that Plan B will only be activated if it comes under "significant pressure".

Plan B includes working-from-home guidance and the mandatory use of face masks.

READ MORE: Humza Yousaf vows action amid fears COP26 could lead to Covid surge

Finn explained that while vaccines are very effective at stopping people from getting seriously ill, they are not so effective at stopping infections altogether or stopping the virus from spreading.

"They do have an effect on that, but they're not by themselves going to be enough at the present time to keep the spread of the virus under control," he said.

"And we do need to see people continuing to make efforts to avoid contact, to avoid transmission, and to do other things as well as get vaccinated if we're going to stop this rise from going up further," he told Trevor Phillips On Sunday on Sky News.

Finn added: "I would like to re-emphasise the fact that the vaccine programme by itself, in the current situation, even if things go optimally, is not, in my opinion, enough to bring things under control.

"We do need to have people using lateral flow tests, avoiding contact with large numbers of people in enclosed spaces, using masks, all of those things now need to happen if we're going to stop this rise and get things under control soon enough to stop a real meltdown in the middle of the winter."

Asked if it is time to bring in Plan B to tackle coronavirus, Chancellor Rishi Sunak said "at the moment the data does not suggest that we should be immediately moving to Plan B".

He told BBC One's The Andrew Marr Show: "Well, the Prime Minister actually just said that we're looking at the data all the time, as you would expect us to.

"We're monitoring everything, but at the moment the data does not suggest that we should be immediately moving to Plan B, but of course we will keep an eye on that and the plans are ready."

Vaccines Minister Maggie Throup claimed Plan A is "working" and "where we need to be".

Asked where case numbers will have to get to before the public will be asked to work from home, Throup told LBC: "The public has been very patient in doing what we've asked them to do.

"And I think Plan A has actually opened up people's lives and that's so important because if we do need to take further measures I'm sure they'll have appreciated exactly the freedoms we've been able to offer them at this time.

"Plan A is working, as I said, the data right now shows that Plan A is working.”