Several experts have warned that the UK could face a lockdown Christmas unless action is taken now to stem coronavirus cases. Here, the PA news agency looks at the evidence.

– Is Christmas at risk?

It depends on who you speak to. For some scientists, the case numbers for Covid-19 are already out of control, averaging around 40,000 new infections per day over the last seven days.

When asymptomatic cases are taken into account, experts tend to agree the true figure could be around 100,000 per day or more.

Most of these are being driven by children and younger adults, though Government scientists tend to think this “child epidemic” could burn out before long as so many will have been infected.

But there is no doubt that, while hospital admissions and deaths remain mercifully low compared with the January peak, there is concern they will rise in the coming weeks, tipping the NHS into a period of intense pressure.

– Does this mean we could face a Christmas lockdown?

Asked on Friday about the possibility of a winter lockdown, Prime Minister Boris Johnson said there is “absolutely nothing to indicate that that is on the cards at all”.

Chancellor Rishi Sunak also said the vaccine rollout and booster jabs make a lockdown or “very significant economic restrictions” unlikely.

On Monday, Health Secretary Sajid Javid said he thinks Christmas will be “normal”, although he has suggested this is contingent on people “playing their part”, such as through getting jabs.

However, Government adviser Professor Peter Openshaw told BBC Breakfast on Saturday that he fears “another lockdown Christmas if we don’t act soon”.

He said getting measures in place now in order to “get transmission rates right down” is key to having “a wonderful family Christmas where we can all get back together”.

Former vaccines tsar Dame Kate Bingham has also said she is worried about having another Christmas “on Zoom”.

– What is Plan B?

The Government is under fire from NHS leaders and some scientists for not implementing its Plan B, which could see the return of mandatory face coverings indoors, guidance to work from home, and vaccine passports.

The plan is designed to protect the NHS from “unsustainable pressure” – though there is no agreed definition of what that means.

The Government has said the NHS is not under unsustainable pressure at the moment, but some health leaders say this is not true.

Introducing the plan could be complicated by the fact that the Scientific Advisory Group for Emergencies (Sage) has said the measures should be brought in in unison, though telling people to work from home would have the biggest impact.

– How many cases are too many?

The Government has said it is looking at all the data in the round on a daily basis, including Covid-19 cases, hospital admissions and deaths.

Health Secretary Sajid Javid has repeatedly warned that recorded cases could hit 100,000 per day over the winter.

For now, deaths are nowhere near previous peaks and are averaging around 136 per day.

But, for the NHS, this is not just about Covid cases. Winter is likely to bring sustained pressure from seasonal flu hospital admissions, the usual winter trips and falls, and the mammoth task of continuing to clear the care backlog caused by the pandemic.

Dr Nick Scriven, former president of the Society for Acute Medicine, said: “Areas of the NHS are currently experiencing conditions outside of anyone’s experience and this comes hot on the heels of two years of unrelenting pressure.”

– What do pubs and restaurants think?

UK Hospitality chief Kate Nicholls has warned that the Christmas season is “desperately important” for the survival of pubs, bars and restaurants as it resists calls for Plan B to be brought in.

She said: “A lot of businesses are still fragile. Any knock at this point in time could have an impact on viability. People will just go to the wall.”

Phil Urban, boss of pub and restaurant chain Mitchells & Butler, has also said: “People are very nervous and if you move to Plan B, it puts Christmas at risk.

“The industry is not out of the woods, and just as we get our momentum back we’d have the rug pulled out from under us.”