The nearly two-decade-old restriction on carrying liquids over 100ml in hand luggage at airports is largely ineffective and constitutes 'security theatre,' according to Bruce Schneier, a security technologist and fellow at Harvard University.
Schneier stated that the rule is not based on genuine security threats but rather on a compromise that wouldn't be logical if it were a significant security issue. He highlighted the inconsistency of finding a prohibited liquid resulting in its confiscation and the passenger's passage, contrasting it with the more severe consequences for attempting to carry a weapon.
"They're not doing it based on security, they're doing it based on a compromise, which would make no sense if it was a security problem," Schneier told The Telegraph's The Travel Expert podcast. "If I walk through airport security with a gun and they find it… they ruin my day. If I walk through security with a bottle of liquid and they find it, they throw it in the trash and let me through."
He further elaborated on the lack of penalty for failure, suggesting it incentivizes repeated attempts. "Because there's no penalty for failure, there's no reason not to try multiple times," Schneier said. "Here's something so dangerous that you can't take it on an aeroplane, yet so safe that [security officers] will throw it in a bin next to them."
The original liquid limits were implemented in the UK in August 2006 following the discovery of a plot by Islamists to smuggle liquid explosives disguised as beverages onto a plane. While this led to an initial temporary ban on all liquids, the restriction was later reduced to the 100ml limit in November of that same year.
However, many airports are now phasing out this rule as they integrate new scanning technology. In January 2026, Heathrow Airport became one of the largest airports globally to fully remove the 100ml liquid restriction. This change was facilitated by a £1 billion investment in new scanners that allow passengers to keep liquids and larger electronic devices in their hand luggage during security screening. Other UK airports, including Birmingham, Bristol, Gatwick, and Edinburgh, have also completed the rollout of this new technology.
