Vaccine certificates could play a role in allowing the return to normality - but not until after everyone has been offered the jab, Boris Johnson has said.
The Prime Minister said a review into the viability of coronavirus health certificates could be expected by April 12, as he confirmed that ministers were considering the idea.
Mr Johnson suggested they could also be based on whether people have developed Covid antibodies after getting the virus, as well as vaccination and negative tests.
It comes after landlords raised concern at his suggestion on Wednesday that punters could be required to provide vaccine certificates before getting through the door.
Speaking on a visit to a nursery in Greenford on Thursday, he told reporters: "I do think there is going to be a role for certification.
"What we said is we'll be reporting on the work of the certification group in early April, either on April 5 or April 12.
© Philip CoburnBoris Johnson suggested Covid certificates might not be possible until everyone has been offered the vaccine
"There are lots of difficult issues because there are some people who for medical reasons can't get a vaccination, pregnant women can't get a vaccination at the moment, you've got to be careful about how you do this.
"You might only be able to implement a thorough-going vaccination passport scheme even if you wanted such a thing in the context of when absolutely everybody had been offered a vaccine."
He added: "There are three basic components. There's the vaccine, there's your immunity you might have had after you've had Covid, and there's testing - they are three things that could work together.
"No decisions have been taken at all. One thing I will make clear is none of this is obviously going to apply on April 12 when it will all be outdoors anyway."
This breaking story is being updated.