Anyone who owns a stainless steel water bottle should be reminded of an important airport security rule that has changed at some UK airports. The regulations around liquids at airport security are evolving, but one particular rule could trip up travellers who are not paying attention. Those packing a reusable drinks bottle for their holiday—especially metal ones, such as stainless steel—will need to remember an extra step when passing through security.
New Scanners and Liquid Rules
Many UK airports now allow passengers to keep liquids in their bags at security checkpoints, thanks to the introduction of cutting-edge scanners. Some have even begun phasing out the two-litre liquid rule, bringing back the two-litre limit per container. As of May 2026, the two-litre liquid rule is operational at London Heathrow (all terminals), London Gatwick, Birmingham, Edinburgh, Bristol, Belfast International, and Belfast City. At most airports, there is no cap on the number of bottles you can carry—whether the 100ml rule remains in force or not.
The Metal Bottle Exception
The only exception to this appears to be for passengers travelling with a metal drinks bottle. These must still be emptied before going through security, even at airports where the 100ml rule has been scrapped. The explanation is that the new scanners are unable to penetrate the double-layer insulation on these bottles, making it safer for travellers to pass them through the scanners empty. Most airport terminals offer free water bottle refilling stations after security.
Dedicated "liquids disposal" sinks and bins are located directly in front of the security screening lanes. It is advisable to check your specific UK airport’s website for the latest rules.
Specific Airport Guidance
Edinburgh Airport, for example, has confirmed that passengers must empty any liquids from metal bottles ahead of security screening. 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 generally pass through security scanners without issue. However, some upgraded airports, such as Gatwick, may ask that passengers remove drinks from these as well. Its website reads: "You can take any empty drink containers (plastic or metal) of any size through security."
Other Items That May Cause Delays
Anyone passing through the airport this year should get clued up on any fresh rules and regulations that might cause complications or hold-ups before their flight. Brits have been warned that packing one particular item could see you pulled aside at airport security. Countless travellers remain completely unaware that a seemingly innocent item could be behind their delay at the scanners, as its shape can raise security staff's suspicions. If you are jetting off somewhere with dodgy WiFi, or simply fancy a bit of evening entertainment, you might well be considering packing a deck of playing cards, UNO, or another card game.
Packing any kind of playing cards can set off a security headache. Ian Cava from the Transportation Security Administration (TSA) claims that the shape of a deck of cards could prompt additional screening. The way that they are stacked and their density can give the impression that something could be hidden within. Ian's advice is for passengers to remove the cards from their hand luggage and place them in the tray next to their bag, along with other belongings such as their mobile phone. "This helps speed up the process and reduces the likelihood of delays," he said.
