TRANSPORT Secretary Grant Shapps said the data "continue to look good" domestically to allow limited international travel from May 17 at the earliest.

He told Sky News: "The earliest possible unlock is May 17, so stage three of the unlock, we won't have international travel before that.

"I have to say that so far the data does continue to look good from a UK perspective, notwithstanding those concerns about where people might be travelling to and making sure we're protected from the disease being reimported.

"I will set out towards the beginning of May ... which countries fall into the various different categories."

Mr Shapps said the NHS app is being worked on to become a health certificate for international travel.

He told Sky News: "In terms of vaccine certification, I can confirm we are working on an NHS application, actually it will be the NHS app that is used for people when they book appointments with the NHS and so on, to be able to show you've had a vaccine or you've had testing.

"I'm working internationally with partners across the world to make sure that system can be internationally recognised, as that's the way forward.

"Actually, I'm chairing a meeting of the G7 secretaries of state for transport, my equivalents from America and Canada and all the G7 countries, next week on exactly this subject."