Liquids, aerosols and gels as well as pastes, lotions and cosmetics have to be 100ml at all EU airports from today (September 1). The European Commission announced on July 31 that it would would be “temporarily” reintroducing the restriction on liquids carried in hand luggage.

No container for any liquid, aerosol or gas can be above 100ml. At most airports liquids must be carried within a resealable clear plastic bag with a maximum volume of one litre.

Europe’s branch of Airports Council International (ACI) said that the move will result in “significant operational strain” and “the deployment of additional staff”. The liquids rules were initially introduced in 2006 as “a temporary measure” to protect against explosives after a “liquid bomb plot” on a transatlantic flight.

ACI has U-turned on the rules, reintroducing the 100ml liquid hand luggage limit, even at airports with new C3 scanners. It is hoped that once the scanners are up and running, passing through airports will be much a easier and smoother process for travellers.

The 100ml limit will apply to travel hubs in countries including Germany, Ireland, Italy, Lithuania, Malta, the Netherlands, and Sweden, where the new technology has been installed already. Included in those are Munich Airport, Dublin Airport, Amsterdam Schipol Airport, Malta Airport, Rome Fiumicino Airport, Milano Malpensa Airport, Frankfurt Airport and Stockholm Arlanda Airport.

Travellers have been warned that confusion, delays and chaos will follow at airports. Anton Radchenko, aviation expert and Founder of passenger rights website AirAdvisor, said last month: “This sudden reintroduction of the 100ml liquid regulation is a big blow to the passenger experience.

“It raises serious questions for the EU regulatory authorities because their decision-making has been all over the place. Who are passengers supposed to trust? You lift the ban one day and then within a month, reintroduce it. It’s a big mess.”