Brussels has been accused of treating the UK with 'contempt' by not announcing which EU countries will implement the new visa arrangements for non-EU citizens - despite the rules coming into force today.
As the new Entry/Exit System (EES) digital border system goes live, experts are warning that British travellers could face queues of up to four hours at some airports to get through security.
But many will not know if their plans are even affected by the changes until they arrive at the airport, as the scheme is being brought in gradually across the EU.
The EES requires Britons and other non-EU citizens to register at the EU border by scanning their passport and having their fingerprints and photograph taken at an electronic booth.
These will be checked at every entry and exit point, and the visa will have to be renewed every three years.
Critics last night hit out at the EU's failure to share key details, with one senior MP describing it as a form of 'bullying'.
Shadow Transport Secretary Richard Holden MP said: 'Britons should not be surprised at being treated with bullying contempt by the EU and gaslit by Sir Keir Starmer, a man who neatly fills the role as the EU's pet poodle in Parliament.
'It's time for Sir Keir to get off his knees and stand up for Britain.'
As the new Entry/Exit System (EES) digital border system goes live, experts are warning that British travellers could face queues of up to four hours at some airports to get through security.
Critics last night hit out at the EU's failure to share key details, with Shadow Transport Secretary Richard Holden MP describing it as a form of 'bullying'.
Meanwhile Shadow Foreign Secretary Dame Priti Patel said Sir Keir was 'weak' for failing to stand up for Britain in the face of 'excessive demands of the EU'.
Passengers boarding international services from London's St Pancras, the Port of Dover and Eurotunnel's Folkestone terminal will also complete EES checks.
The Government is organising car overflow sites to be used in the event of extreme queues at Dover.
Border Minister Alex Norris insisted the Government was working to 'ensure the rollout goes as smoothly as possible'.
A Home Office spokesman added that the extra checks 'should only take one to two minutes' to complete, though warned they could lead to 'longer waits at busy times'.
But one senior Labour MP admitted the inevitable disruption was set to be 'deeply annoying'.
Passengers may also face questioning about their travel plans, including their accommodation, whether they have travel insurance and if they have enough money to cover their trip.
Answering 'no' to any of the questions could lead to them being interrogated by border guards.