The rules around bringing liquids through airport security are changing, but one rule could catch travellers out if they are not careful. Anyone bringing a reusable drinks bottle on holiday, especially metal ones, such as stainless steel, will need to remember one extra step at security.
Many UK airports now let you leave liquids in your bag at security, thanks to the rollout of new, advanced scanners. Some have even started to scrap the 100ml rule, reintroducing the two-litre limit per container.
As of May 2026, the two-litre liquid rule is in place at London Heathrow (all terminals), London Gatwick, Birmingham, Edinburgh, Bristol, Belfast International, and Belfast City. At the majority of airports, there's no restriction on the number of bottles you can bring with you - regardless of whether the 100ml rule is enforced or not.
The only exception to this rule seems to be if passengers are travelling with a metal drinks bottle. These must still be emptied before going through security, even at airports where the 100ml rule has been replaced.
The reason is that the new scanners cannot see through the double layer of insulation on these bottles, making it safer for passengers to bring them through the scanners empty. Most airport terminals offer free water bottle refilling once security has been cleared.
Edinburgh Airport, for instance, confirmed its passengers will need to empty their liquids from metal bottles before security checks. A statement on its website reads: "If you are carrying metallic or double-walled containers (including vacuum flasks, thermos flasks and metallic water bottles), please ensure the container is empty prior to the security checkpoint. You can then top up your bottles for free after security."
Plastic water bottles of any size should be fine to pass through security scanners. But some upgraded airports, like Gatwick, may ask passengers to remove any drinks from these as well. Its website states: " You can take any empty drink containers (plastic or metal) of any size through security."
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Anyone travelling through the airport this year should familiarise themselves with any new rules and regulations that could cause issues or delays before their flight. Brits have been warned that packing one item could get you flagged at airport security.
Many travellers are completely unaware that a seemingly harmless item could be the culprit behind their hold-up at the scanners, as its shape can raise security staff's suspicions. If you're heading somewhere with unreliable WiFi, or simply fancy some evening entertainment, you may well be thinking about packing a set of playing cards, UNO, or another card game.
However, packing any type of cards can trigger a security problem. Ian Cava from the TSA explained that the shape of a pack of cards could trigger additional checks, and that it might make it seem like something is hidden inside because of how they are packed and their density.
Ian's suggestion is that passengers should take the cards out of their hand luggage and put them in the tray beside the bag, alongside items like their mobile phone. "This helps speed up the process and reduces the likelihood of delays," he said.
