Government ministers will reportedly discuss vaccine and Covid-19 test 'passports' tomorrow.
It comes after months of denial from the Government that any formal certification of vaccine status was being planned.
Just last week, the Mirror reports that Vaccines Minister Nadhim Zahawi denied the Government was looking at introducing an immunity passport.
However a Government spokesperson told Sky News that the UK is "working closely" with international partners in a bid to enable travel, and that there would be an "internationally recognised" approach.
It came as British Airways extended trials of a digital health app to all international flights to the UK.
According to Sky, Ministers will tomorrow meet to discuss "certification" for people who have been vaccinated or tested negative for Covid-19.
Last week, Mr Zahawi said: "One, we don't know the impact of the vaccines on transmission; two, it would be discriminatory and I think the right thing to do is to make sure people come forward to be vaccinated because they want to rather than it being made in some ways mandatory through a passport."
But he added: "If other countries obviously require some form of proof, you can ask your GP - because your GP will hold the records - and of course that will then be able to be used as your proof that you have had your vaccine, but we are not planning to have a passport in the UK."
According to Sky News, the Foreign Office will help design the international certificate system - and the proposal has been signed off by Foreign Secretary Dominic Raab ahead of tomorrow's meeting.
But officials are said to be "nervous" about when to roll the system out - or even announce it publicly.
And it would reportedly not be rolled out until there was "sufficient scientific evidence" on the effects of vaccine and test certificates.
A Government spokesperson did not deny the plan.
They said: "The UK government, like most nations, wants to open up international travel in a responsible safe and fair manner and we continue to be guided by the science.
"We want to ensure there is an internationally recognised approach to enable travel and are working closely with international partners to do so."
Meanwhile, In response to tightening border controls, British Airways announced it plans to increase its trial of the VeriFLY digital health app across all International flights operating into the UK.
The expansion, which will come in to effect from February 15, is aimed at ensuring travellers have all the documentation they need before they fly.
