Amid rising coronavirus rates, the Prime Minister said in the Commons: “We always knew that while we might have driven the virus into retreat, the prospect of a second wave was real and I’m sorry to say that, as in Spain and France and many other countries, we’ve reached a perilous turning point.”
Mr Johnson said a month ago an average of around 1,000 people across the UK were testing positive for Covid-19 every day, adding the latest figure has almost quadrupled to 3,929.
And he said: “I want to stress that this is by no means a return to the full lockdown of March. We’re not issuing a general instruction to stay at home.
“We will ensure that schools, colleges, universities stay open because nothing is more important than the education, health and well-being of our young people.
“We will ensure businesses can stay open in a Covid-compliant way. However we must take action to suppress the disease.”
But a number of new measures were announced including a 10pm curfew for pubs, bars, and restaurants from Thursday, table service only in hospitality venues, and a change in messaging that people who can work from home now should do so again.
Customers must now wear masks in taxis by law, and staff must also do so in shops.
Both staff and customers in indoor hospitality venues must also wear masks, unless eating or drinking.
And the number of people who can attend a wedding has been slashed to 15.
Easements to rules relating to large sporting events and conferences due to take place on October 1 have been cancelled, and businesses will face fines of up to £10,000 or could be closed if they breach regulations.
Mr Johnson said: “No British Government would wish to stifle our freedoms in the ways that we have found necessary this year.
“Yet even now we can draw some comfort from the fact schools, universities, and places of worship are staying open, shops can serve their customers, construction workers can go to building sites and the vast majority of the UK economy can continue moving forwards.
“We’re also better prepared for a second wave with ventilators and PPE, the dexamethasone, the Nightingale hospitals and hundred times as much testing as we began this epidemic with.
“So it now falls to each of us and every one of us to remember the basics – wash our hands, cover our faces, observe social distancing and follow the rules.
“Then we can fight back against this virus, shelter our economy from even greater damage, protect the most vulnerable in care homes and hospitals, safeguard our NHS and save many more lives.”
He told the Commons: "We will spare no effort in developing vaccines, treatments and new forms of mass-testing but unless we palpably make progress, we should assume that the restrictions I have announced will remain in place for perhaps six months.
"For the time being, this virus is a fact of our lives and I must tell the House and the country that our fight against it will continue.
"We will not listen to those who say let the virus rip; nor to those who urge a permanent lockdown; we are taking decisive and appropriate steps to balance saving lives with protecting jobs and livelihoods."
Labour leader Sir Keir Starmer said it is “right” Mr Johnson is announcing further measures, adding: “We support those measures.”
He said: “Just as we supported lockdown in March and the more recent local lockdowns, although with fierce criticism of the way the Government is handling this pandemic, when restrictions are needed the national interest lies in clear communications and cross-party support.”
Sir Keir said families were worried that “the Government doesn’t have a strategy”.
He added: “One day people were encouraged to work in the office, in fact more than encouraged they were openly challenged by the Prime Minister for not doing so, today they’re told the opposite.
“This is a time of national crisis but we need clear leadership.”