The long-standing norm was decided to be reimposed by the EU Commission at the end of July, but it is already in force.

That implies that in airports that had been utilizing modern technology to permit travelers to bring larger volumes of liquid, the cap of 100 milliliters for each individual container will be reinstated.

Airports in the EU, Iceland, Switzerland, Liechtenstein, and Norway (EEA) are all covered by the ruling.

C3 scanners had already been deployed by airports in a limited number of countries, such as Germany, Ireland, Italy, Lithuania, Malta, the Netherlands and Sweden, according to the Europe branch of the Airports Council International (ACI).

The restriction on liquids exists because traditional security equipment, like X-ray machines, cannot effectively detect liquid explosives.

The EU Commission said its decision wasn't "in response to any new threat" but because of a temporary technical issue.

It said information had indicated the scanners' performance "did not meet the standard for which it had been approved".

It comes after plans to lift the 100ml rule across UK airports by June this year were pushed

Major UK airports are believed to have been granted an extension for installing the new scanning technology after they were unable to meet the 1 June deadline.

The 12-month extension was issued by the government on a case-by-case basis and is expected to be enough time for them all to complete the work.

It is not the first time the change has been delayed after it was originally set to come into force in December 2022.

London City Airport became the first in the city to scrap the 100ml limit in April last year.

Thanks to the C3 scanners, passengers departing from City have been able to carry up to two litres of liquid.