The Legal Unpacking of the 100ml Rule

For nearly two decades, the 100ml liquid limit has been the source of much distress for the frequent flyer, a regulatory framework implemented after a foiled 2006 terror plot that transformed the “clear plastic bag” into a mandatory travel accessory. However, as of the new year, we are witnessing a significant legislative and technological pivot. Heathrow Airport has formally announced the completion of its £1 billion security upgrade, joining Gatwick, Birmingham, and Edinburgh in erasing the 100ml rule. 

This shift is driven by the nationwide rollout of Next Generation Security Checkpoints (NGSC). These advanced CT scanners use medical-grade technology to create high resolution 3D images, enabling security staff to virtually rotate and inspect luggage contents without requiring passengers to unpack. From a legal perspective, this represents a major update to the Aviation Security Regulations. The previous 100ml cap was a necessary “blanket” restriction, because traditional X-ray machines could not effectively distinguish between harmless liquids and liquid explosives. With the increased “threat detection” capabilities of the new scanners, the Department for Transport (DfT) has moved to extend the liquid container limit from 100ml to two litres. 

The transition has, however, been far from a smooth take-off. The original government deadline of June 2024 was pushed back multiple times as major hubs like Heathrow and Manchester struggled with the logistical nightmare of installing machines that are notably heavier and larger than their predecessors. In some terminals, floors literally had to be reinforced to support the weight of these “Ford Transit-sized” scanners. This delay created a period of “regulatory fragmentation,” where rules varied terminal by terminal, leading to confusion and the temporary reintroduction of the 100ml limit in June 2024 for “further improvements.” Despite this, flyers can remain optimistic, as the UK governing bodies are seemingly taking active steps to simplify and enhance your travel by plane!