Foreign Secretary Dominic Raab has defended the “balanced, targeted and proportionate” new coronavirus measures amid criticism from some scientists.
In England, people are being told to work from home if they can and rules on face coverings have been expanded.
The measures have exposed a split among scientists. Prof John Edmunds, who advises the government, said they did not go “anywhere near far enough”.
But other scientists say they hope they are a shift towards a coherent policy.
On Tuesday, tighter restrictions were announced in all four UK nations.
Other measures introduced in England include a 10pm closing time for pubs and restaurants and the number of people allowed at weddings has been halved. The fines for breaking the rules are set to increase to £200 on the first offence.
Hospitality venues will also have to close early in Scotland and Wales – but Scotland has gone further, banning people from visiting other people’s homes from Wednesday. Northern Ireland has also already banned households mixing indoors.
In a television broadcast on Tuesday night, Prime Minister Boris Johnson said “we must reserve the right to go further” if cases continue to rise.
He said he was “spiritually reluctant” to infringe on people’s freedoms, “but unless we take action, the risk is that we will have to go for tougher measures later, when the deaths have already mounted”.
In an interview on the Today programme, Prof Edmunds said the lockdown in March which closed schools, the hospitality sector and businesses, had involved a combination of many different measures which brought the R number – which measures how quickly the virus is spreading – down from 2.7 to 0.7.
To stop the epidemic from growing any further, a large range of measures was needed, he said, and cast doubt on the R number being below 1 by Christmas. “I suspect not. There’s a chance, of course there’s a chance,” he said.
“To slow the epidemic down will mean putting the brakes on very hard. I suspect we will see very stringent measures coming in through the UK but it will be too late,” he warned.
The British Medical Association, a medical trade union, echoed Prof Edmunds’ warning that the measures did not go far enough and criticised ministers for hurrying workers back to offices as infection rates were rising.
It said the PM had missed an opportunity to revise the rule of six in England – which allows for gatherings of no more than six people – in light of data suggesting the spread between households was the biggest driver of infection.
Another scientist, Prof Carl Heneghan, from Oxford University, wrote to the government on Monday saying there should be targeted measures to protect the vulnerable because suppression of the virus was increasingly unfeasible.
Speaking to the BBC’s Today, he said the measures seemed to show the emphasis of public policy was moving towards personal responsibility, similar to Sweden.
“There’s a clearer aim that’s happening,” he said. “We’re starting to understand that we’re trying to control the spread of infection as opposed to suppress it.”
He added it was important to give these new measures time to work, maintain a clear and consistent public message and not to panic.