Heathrow, Gatwick and Manchester airports, the BBC reports, have all admitted they won’t have completed their upgrades by then. Consumer champion Which? said it would likely cause confusion this summer after the government’s high profile commitment to phase out the rule in June.

The new generation of CT scanners being introduced at airports across the UK will allow passengers to carry liquids of up to two litres in their hand luggage. They will also be able to leave them in their bags when clearing security, along with electronic devices like laptops.

Teesside airport became the first UK airport to scrap the 100ml rule in March last year, followed a few weeks later by London City airport. Passengers, though, have been warned that while they may be able to take advantage of the rule being scrapped in the UK, they make face restrictions on liquids at their return airport.

The 100ml rule was introduced in 2006 following a failed terror plot. The government had originally sought for airports to make the necessary upgrades by 2022, but the timetable was pushed back to 2024.

Heathrow has introduced new scanners at three of its four terminals, but could not commit to meeting the 1 June deadline. Gatwick, meanwhile, said it had made "significant progress" at both of its terminals, but did not expect to complete the upgrade until "early next year".

Manchester Airports Group, which owns Manchester, Stansted and East Midlands airports, said despite making "good progress" on its rollout, it was unlikely to be complete until 2025.