The government has launched a new public health campaign urging the public to "stay at home" in a bid to get the country to comply with lockdown rules.
People are also being warned to act as if they have the virus amid fears people are beginning to tire from measures, such as social distancing, which can reduce the spread of the disease.
Friday marked the UK's worst day for new infections and deaths since the pandemic began, with a record 68,053 Covid-19 infections and 1,325 deaths. With rising infections, the hospitalisation rate and death toll is only likely to worsen.
The new campaign is across multiple media platforms, including TV, radio, newspapers and social media.
Professor Chris Whitty, who fronts the advert, says: "Covid-19, especially the new variant, is spreading quickly across the country. This puts many people at risk of serious disease and is placing a lot of pressure on our NHS.
"Once more, we must all stay at home. If it's essential to go out, remember: wash your hands, cover your face indoors and keep your distance from others.
"Vaccines give clear hope for the future, but for now we must all stay home, protect the NHS and save lives."
Prime minister Boris Johnson says infections are rising at an "alarming rate" and hospitals are under "more pressure" than at any other point during the pandemic.
He added: "The vaccine has given us renewed hope in our fight against the virus but we must not be complacent."
The UK has been particularly badly impacted by the spread of a new variant which emerged in this country.
The new highly contagious strain is thought to make the virus up to 70% more transmissible, however there is no evidence to suggest it is more deadly.
Lockdown measures have been put in place to try to stop the spread of the disease, however there are fears it might not be enough.
Dr Simon Walsh, deputy chair of the British Medical Association’s consultants committee, said conditions in hospitals are likely to get worse before they get better.
The London-based emergency care doctor said the epidemiology from the previous wave indicates the situation is likely to worsen over the next two to three weeks.
He told BBC Breakfast: “I’m afraid all of us who are working on the front line believe, and this is based on the evidence I’m afraid, that it is going to get worse before it gets better.”
He said critical care was having to be spread “more and more thinly”, with as many as three patients per intensive care nurse, rather than the usual standard of one-to-one care.
The Government must both ramp up vaccinations and ensure the appropriate PPE is available for healthcare workers, to make sure they can continue going to work, rather than being struck down by the virus.
He said: “They need to ensure that PPE supply is there when we need it, because we were let down I’m afraid in the first wave by that and so our confidence needs to be restored by the Government in vaccinating and ensuring that those PPE items are in place."
ITV News Science Editor Tom Clarke said: "A senior government advisor suggested it might not be enough - it might just be enough to hold it level. We really are waiting for that vaccine but it doesn’t mean we can sit around and do nothing."
Tom Clarke on the worrying Covid-19 stats
He warned: "We need to work quite a bit harder now, with the lockdown, to get cases down, otherwise we’re going to see a lot more people going to hospital. Unfortunately, we’re going to see those cases continue to rise and deaths continue to track them, with something of a delay, for a couple of weeks at least."
London has been particularly badly affected, with mayor Sadiq Khan declaring a major incident at hospitals as the capital struggles to deal with patients.
Mr Khan said that in some parts of the London one in 20 people has coronavirus – compared to the England average of one in 50 – while there are 35% more people in hospital with Covid-19 than at the peak of the pandemic in April.
Latest Covid-19 figures in the UK
The declaration of a major incident means that events are beyond the scope of business-as-usual operations and require special arrangements to be implemented by one or more emergency responder agency.
London’s regional director of Public Health England Professor Kevin Fenton said the situation now is the “biggest threat our city has faced in this pandemic to date”.