Digital Covid vaccination certificates are unlikely to be in place for the restart of international travel – but the government hopes to digitise its Passenger Locator Forms by the summer.

Transport secretary Grant Shapps confirmed plans to use an NHS app as verification that a UK traveller has had a Covid vaccine earlier this week – and that there would be both digital and non-digital options.

A source close to Global Travel Taskforce talks said Covid certification requirements by destinations could be in place by the earliest possible restart of international travel, on May 17, but making vaccination status digital by then would be a “big ask”.

They said: “Government is aware it needs to provide some certification for people who are fully-vaccinated if that’s a requirement of the destination, but it may not be until the [taskforce’s June 28] review.”

The government’s primary focus is making Passenger Locator Forms digital before summer so they can be read at UK airports’ e-gates, in order to avoid “untenable” arrivals queues in July and August, the source explained.

Shapps suggested as much when updating MPs on Thursday. He said: “We’re working with Border Force on e-gates but it is not straightforward, not least because it requires both hardware and software.”

Tourism minister Nigel Huddleston told the World Travel & Tourism Council’s global summit earlier this week that the UK is working with other countries to align international travel, including vaccine certification.

But he warned: “It is not going to be seamless to travel over the next few months, and potentially years, but we want to make it as simple as possible.”

Delegates at the Mexico event welcomed the European Union’s decision to allow vaccinated Americans to visit this summer – but Brussels is yet to open discussions with the UK about mutual recognition of vaccine certification.

Fernando Valdés Verelst, Spain’s tourism minister, told delegates the country would welcome visitors from June and is trialling certification at all 46 airports in May.

However, he warned that travellers also need more certainty when returning to their home countries – without which only “one side of the equation” is solved.

Greece will open from May 14 for tourists with proof of vaccination or a negative test. Tourism minister Harry Theoharis told delegates his country’s progress will put pressure on others to open borders.