Some nightclubs have begun asking revellers to show Covid passes before they will be allowed through the door.
The Government has said it wants to make vaccine passports mandatory for some settings – such as nightclubs – and crowded events from the autumn.
Earlier this month Boris Johnson announced people would be required to be fully vaccinated from the end of September.
Now, a club night in Manchester and London will ask patrons for the proof at the point of entry for both venues.
For a pass clubbers must have had a negative Covid test, have existing antibodies or be fully vaccinated, with two doses of a jab.
The requirement is for the Ultimate Power Club night set to take place at the two cities.
Organisers said: “We understand we are asking our customers to follow extra steps at this point and we need you more than ever.”
Other venues demanding clubbers show their Covid status on entry include the O2 chain, run by Academy Music Group, with more than a dozen venues across England.
On its website club bosses said that anybody attending their venues will also have to show a so-called Covid pass.
Explaining the move the firm said: “Whilst Covid-status certification might not be mandated by law right now, the latest government guidance states that venues such as ours – where people are likely to be in close proximity to others outside their household – are encouraged to use the NHS Covid pass to certify Covid status for all visitors.”
It comes after the NHS app was upgraded to allow it to be used as a vaccine passport in the UK as well as abroad.
A section appeared on the app for “domestic” use in recent days, allowing people to get the NHS Covid Pass through testing, full vaccination, natural immunity or an exemption.
It states: “You may need to show your NHS Covid Pass at places that have chosen to use the service”.
The app previously provided a Covid certificate for international travel or for the Government’s events research programme, which trialled mass gatherings at events like the Euros finals and the Brit Awards.
Lib Dem Home affairs spokesman Alistair Carmichael accused the government of committing to vaccine passports “by stealth”.
He said: “This deceitful move is deeply shameful. We now have a new ID card snuck onto our phones without even as much as a whisper from the government.”
He added: “They must recall Parliament now if they are serious about this.”
Meanwhile, Health Secretary Sajid Javid said young people should think of Covid-19 vaccines as “liberating”.
Speaking at a vaccination centre in Little Venice, London, he said that “the one area where we need to do more collectively” is to get 18 to 29-year-olds to take up the offer of a jab.
He said: “What I would say to that group of people is please get vaccinated for your own benefit, for your loved ones, but for your wider community.”
Asked about how widespread the requirement to show a vaccine passport might be, Mr Javid highlighted the planned introduction of their use for England’s nightclubs by the end of September.