Covid passports are set to be introduced for the first time in England, as Boris Johnson warned that people must exercise "extreme caution" despite the scrapping of legal restrictions.
On Monday night, the Prime Minister revealed that nightclubs and other venues with large crowds would be urged to adopt Covid certification "as a matter of social responsibility".
He said relevant businesses should "make use" of the NHS Covid app, which shows proof of double vaccination, a recent negative test or natural immunity, as "a means of entry".
It marked a climbdown by the government after Nadhim Zahawi, the vaccines minister, insisted in February that "we are not planning to have a [Covid] passport in the UK".
Amid concern over a slowdown in vaccine take-up, the recommendation to use vaccine passports could become mandatory, government documents reveal.
It comes Emmanuel Macron, the French president, suggested Covid jabs could be made mandatory and announced the extension of a vaccine passport scheme. In Ireland, it has been announced that indoor hospitality will reopen only for those who are fully vaccinated.
For Britons, proof of Covid status is already required in order to travel to some countries and to avoid quarantine on return from many popular holiday destinations.
However, in a strengthening of the messaging on trips abroad, Mr Johnson said: "The single most crucial thing now is that you get that jab, a jab that can protect you and your family and allow you, for instance, to go on holiday."
Amid growing pressure over low takeup among some groups, the Government has already said that jabs will be mandatory for care home workers in England. MPs will vote on the move on Tuesday.
Speaking at a Downing Street press conference on Monday, Mr Johnson confirmed that all legal Covid restrictions will be scrapped from next Monday, July 19, in step four of his roadmap out of restrictions.
Despite the date having been called "freedom day", the Prime Minister unveiled a series of new government recommendations to replace these rules – something critics alleged would fuel confusion. But he said: "I cannot say this powerfully or emphatically enough – this pandemic is not over."
The public will be urged to "limit the close contact you have with those you do not usually live with" and to continue to wear face masks in crowded, enclosed places.
Last week, Mr Johnson said face coverings would become a "personal choice" after the legal requirement to wear one was scrapped. Workers are asked to return to offices "gradually".
The end of legal regulations "should not be taken as an invitation for everybody to have a great jubilee", he said, adding that people "cannot simply revert instantly from Monday 19 July to life as it was before Covid".
He revealed that the Government would keep Covid data under review "probably, I’m afraid, into next year" and indicated that he "will not hesitate" to bring back legal restrictions if needed.
The Government will review whether to continue "or strengthen" public and business guidance in September.
It marked a stark change of tone from February, when Mr Johnson said the Government wanted to see progress that was "cautious but irreversible".
Ministers have predicted that new Covid cases could total more than 100,000 a day within weeks.
Mr Johnson acknowledged that the current wave of cases would mean more hospital admissions and deaths, but insisted the nation had arrived at a stage in the pandemic "when there is no easy answer and no obvious date for unlocking".
He said delaying to the autumn would risk reopening at a time when schools are back from the summer holidays and people are spending more time indoors as the weather turns colder.
Scientific advisers on Sage expect hospitalisations to reach at least 1,000 a day once restrictions lift, new papers revealed. Deaths could reach up to 200 a day, though a high degree of uncertainty remains.
Updated guidance published on Monday set out the "key protections" that will be retained after step four, while cases are "high and rising".
Businesses and large events will be "encouraged and supported" to use the NHS Covid app "in high-risk settings", it said, adding that the Government would work with organisations where people will mix "in close proximity" with others outside their household.
The document warned, however, that if sufficient measures are not taken to limit infection, the Government will "consider mandating certification in certain venues at a later date".
Covid passports have been trialled at some events over the summer as part of a government research programme.
Steve Baker, the deputy chairman of the Tory lockdown-sceptic Covid Recovery Group, accused the Government of introducing a "two-tier society" with the move to introduce Covid certification. He warned on Twitter that ministers "must not restrict basic freedoms only to restore them to some", adding: "We are so far down the rabbit hole, we have forgotten we fell in."
So far, 87 per cent of England’s adult population has received a first Covid vaccine jab, with the vast majority – 96 per cent – returning for a second.
However, almost half of male 18 to 24-year-olds remain unvaccinated more than three weeks after access to jabs was opened to adults of all ages. Just 42,000 first doses were given on Sunday, the latest available data shows. At the peak, 752,308 vaccines were given in a day.
How many people have been vaccinated?
The patchwork of new recommendations sparked a backlash from some business leaders.
Claire Walker, the co-executive director of the British Chambers of Commerce, warned that the "confusing" approach could "damage public confidence", give firms a "huge logistical headache" and risk "splintering" the economic recovery.
She called for legal clarity, warning that business leaders are not public health experts and face "contradictory advice" from official sources.
Six guidance notes will be published by the Government this week, outlining advice for employers in various settings after next Monday.
They will update and consolidate 14 documents currently in circulation and are expected to stress the importance of ventilation and the need to continue with risk assessments.