Boris Johnson has warned that harsher lockdown rules may be needed as the UK faces a “perilous moment” in the fight against the pandemic.
The prime minister said 2.4 million people had so far been inoculated against coronavirus while on a visit to a new mass vaccination centre in Bristol in south-west England.
The clinic is one of seven that opened on Monday to help the National Health Service achieve its goal of vaccinating 15 million people by mid-February.
The sites, in Bristol, London, Newcastle and Manchester, include football stadiums and a horse-racing course.
The Abu Dhabi-owned Excel Centre in London is also among the venues.
Thousands of people per week will be immunised at the clinics.
But Mr Johnson warned against complacency with the arrival of vaccines as he emphasised the grave burden on public healthcare.
“It’s a race against time, because we can all see the threat that our NHS faces, the pressure it’s under, the demand in intensive care units, the pressure on ventilated beds, even the shortage of oxygen in some places,” he said.
“This is a very perilous moment.”
Mr Johnson said about 40 per cent of people aged 80 or above had been immunised, as had 23 per cent of elderly care home residents.
He said stricter lockdown rules would be enforced if people failed to follow the existing rules.
“Where we have to tighten them, we will,” he said.
Britain's health minister Matt Hancock on Monday said that he was confident that ambitious Covid-19 vaccination targets would be met after reaching an average of 210,000 shots a day between Thursday and Sunday.
"We've got a continued increase in the rate of vaccination. This is happening right across all four nations of the UK," he said at a news conference of the government's target of vaccinating 15 million of the elderly, vulnerable and frontline workers by mid-February.
"It means that we are on track to meet that target. It's not going to be easy but we are going to get there."
Professor Chris Whitty, England’s chief medical officer, pleaded with the public to stay at home unless it was absolutely necessary to go outside.
He told the BBC: “We’re now at the worst point of this epidemic for the UK. The numbers at the moment are higher than they were in the first peak by some distance.”
Asked whether it was too dangerous to meet people outside, Prof Whitty said: “The new variant undoubtedly makes every situation slightly more dangerous. The probability of transmission has gone up.”
Those who were vaccinated at Epsom Downs Racecourse, near London, on Monday said they were relieved.
“I feel this is the way back. I can’t understand anybody not wanting to have it,” said Moira Edwards, 88.
The mainly elderly recipients of the jab, some of whom used walkers, sticks or were pushed in wheelchairs to get to the centre, were given “I’ve had my Covid vaccination” stickers.
Simon Stevens, NHS England’s chief executive, was confident the “stretching” vaccination target could be hit despite reports of supply shortages.
“This is a sprint to mid-February, then it is a sprint from mid-February to rest of April to extend the vaccination to other groups, then it will be a marathon from the summer and autumn,” he told a parliamentary committee. He said all Britons would be offered the shot by the end of the year.
Meanwhile, proposals to strengthen lockdown restrictions include banning people from two separate households meeting for exercise after speculation that people are exploiting the exemption to socialise with friends.
Stricter rules for supermarkets, such as one-way systems and mask-wearing in outdoor queues, will be a particular focus, while mask-wearing could also be enforced in offices and crowded spaces outside.
The UK last week reported a record 1,325 virus deaths over a 24-hour period.
The full death toll now stands at more than 80,000, the highest in Europe.
At Leatherhead, near Epsom, bodies were being stored in a temporary 1,400-capacity mortuary because there was no space at local hospitals.
The local council said 170 bodies, more than half of which had been Covid fatalities, were being held at the makeshift facility, but the county would be in “real difficulty” if numbers rose further.
