People must take lockdown seriously as “we are now in the eye of a storm”, an expert has warned, amid record hospital admissions for Covid-19.
Prof Peter Horby said the situation was “much worse” than in March.
Health Secretary Matt Hancock said “every flex in the rules could be fatal”.
It comes after almost 60,000 new cases of coronavirus were reported in the UK on Saturday and the number of deaths after a positive test passed 80,000.
Labour leader Sir Keir Starmer said the rules were tough but “may not be tough enough” and called for the government to hold daily press conferences to avoid “mixed messages”.
Prof Horby, who is chairman of the New and Emerging Respiratory Virus Threats Advisory Group (Nervtag), said there may be “early signs that something is beginning to bite” in terms of the restrictions – but if they did not then stricter measures would be needed.
He told the BBC’s Andrew Marr Show: “I really hope people take this very seriously. It was bad in March, it’s much worse now.
“We’ve seen record numbers across the board, record numbers of cases, record numbers of hospitalisations, record numbers of deaths.”
“We are in a situation where everything that was risky in the past is now more risky,” he said.
Prof Horby said the early signs were encouraging that the vaccines would be effective against the new Covid variants – first identified in the UK and in South Africa – and he did not want people to “hide under the duvet”.
“We can see the end game now,” he said.
Higher cases inevitably mean more hospitalisations and more deaths.
The most recent figures show that, on average, 894 people per day are now dying within 28 days of a positive Covid test, up from 438 at the start of December.
The spike in cases since Christmas means that figure is almost certain to get worse before the most recent lockdown measures can start to have any affect.
Scientists think the new variant of the disease is more “transmissible”, possibly because each infected individual produces more of the actual virus – sometimes referred to as the viral load.
Vaccination should help to protect the most vulnerable from serious symptoms but we don’t yet know if receiving the jab stops an individual contracting the virus and passing it on to others.
Scientists say that may mean even tougher restrictions will be needed to bring the R-number below one and start to reduce the overall size of the pandemic.
Mr Hancock told Andrew Marr the NHS was under “very serious pressure” and said “every time you try to flex the rules that could be fatal”.
He did not rule out strengthening the current rules in England but said staying at home was the “most important thing we can do collectively as a society”.
Mass community testing is to be rolled out this week, the government has said, and the health secretary said that around two million people had been vaccinated, with some 200,000 jabs being given daily.