Brits could face an autumn ban from meeting family while there are fears pubs may have to close to allow children to return to school.
Chief Medical Officer Chris Whitty said England has “probably” reached the limit of easing the coronavirus lockdown, or is close to it after plans to ease more restrictions were cancelled.
Boris Johnson reversed the decision to allow casinos, bowling alleys and beauty salons to reopen on August 1 for at least a fortnight.
But they could have to wait even longer after a recent spike in cases means it may no longer be possible to ease social distancing measures any further.
The Prime Minister was asked if there would have to be “trade-offs” to meet his goal of getting all pupils back in England’s schools from September 1.
And there are fears from experts that these could include a national ban on social meet-ups indoors and possibly the closing of pubs.
People may also once again be asked to avoid using public transport, reports say.
He replied at a press conference: “Your basic point is a very good one about the trade-offs that we’re looking at here.
“I do believe getting our children back to school on September 1… that should be a national priority.”
And Prof Whitty spelt out the grim situation more clearly.
He said: “The idea that we can open up everything and keep the virus under control is clearly wrong.
“I think what we’re seeing from the data from ONS and other data is that we have probably reached near the limit or the limits of what we can do in terms of opening up society.
“So what that means potentially is that if we wish to do more things in the future, we may have to do less of some other things.
“And these will be difficult trade-offs, some of which will be decisions for government and some of which are for all of us as citizens to do.
“But we have to be realistic about this. The idea that we can open up everything and keep the virus under control is clearly wrong.
“And what we’re seeing is that that we are at the outer edge of what we can do – and therefore, choices will need to be made.
“People I think are very clear, for example, that schools are an absolute priority for the welfare of children.”
The trade-offs could see families asked to avoid using public transport or meeting other households from September.
Some experts also fear pubs and restaurants may also have to close in order to allow schools to reopen fully in September.
Sir Jeremy Farrar, Chair of the Wellcome Trust, told The Sun reopening schools was about “choices and trade-offs” that would include workplaces, public transport, pubs and “many others”.
It comes as the Government’s scientific advisory group for emergencies – or SAGE, says there needs to be “sufficient headroom” in the rate of Covid-19 infections in order for schools to reopen safely.
On June 23, the group said there “may be a need to change measures at the end of the summer in order to be able to keep R below 1 whilst proceeding with the planned reopening of schools”.
A meeting on July 9 highlighted that the spread from children to adults “appears to be low” and outbreaks in schools “are extensions of community outbreaks and comprise small numbers, rather than indicating that schools are high-risk settings”.
However, scientists warned it is “important to ensure that there will be enough ‘room’ in terms of the epidemic to open schools in September”.
It follows the news that local lockdown measures were announced in parts of the North West of England and areas of West Yorkshire, banning people from different households meeting indoors or in gardens following a spike in virus cases.
Mr Johnson told the briefing on Friday: “As we see these rises around the world, we can’t fool ourselves that we are exempt. We must be willing to react to the first signs of trouble.”
He added: “We cannot be complacent and I won’t stand by and allow this virus to threaten to cause more pain and more heartache in our country.”
He said that, with numbers rising, “our assessment is that we should squeeze that brake pedal in order to keep the virus under control”.
The measures leave Mr Johnson’s prediction that things would return to normal by Christmas in tatters amid fears of a second wave of coronavirus.
The Office for National Statistics released its latest data on new Covid-19 infections which show there were 4,200 fresh cases from July 20 to 26 – up from 2,800 the previous week.
And the Government’s Scientific Advisory Group for Emergencies announced it is “no longer confident that R is currently below one in England”.
As the UK death rate rose by 120 to 46,119 on Friday, Mr Johnson insisted the reopening of society had always been “conditional on continued progress against the virus”.
He said: “The prevalence of the virus in the community, in England, is likely to be rising for the first time since May.”
The PM also introduced yet another slogan – “Hands, face, space, get a test”. Explaining it, he added: “We need to follow the rules, wash our hands, cover our faces, keep our distance and get a test if we have symptoms.”