The long-standing rule requiring airline passengers to limit liquids in carry-on baggage to 100ml is a form of "security theatre" that lacks a genuine security basis, according to a Harvard University expert. Bruce Schneier, a security technologist and fellow at Harvard, stated that the restrictions are ineffective because they are not enforced with severe penalties.
"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," Schneier explained in an interview with The Telegraph's The Travel Expert podcast. "Because there's no penalty for failure, there's no reason not to try multiple times. 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 100ml liquid limit was introduced in the UK in August 2006 following the discovery of a plot by Islamists to smuggle liquid explosives disguised as soft drinks onto flights. While the initial ban was temporary, it was reduced to the 100ml restriction in November of that year.
However, many airports globally are now phasing out this rule as they adopt new scanning technologies. Heathrow Airport, one of the world's busiest, fully removed the 100ml limit in January of this year after a £1 billion investment in new scanners. These advanced scanners allow passengers to keep liquids and larger electronic devices in their hand luggage. Birmingham, Bristol, Gatwick, and Edinburgh are among other UK airports that have also implemented the new scanning technology.
Schneier contends that the rule was a result of a compromise rather than a direct response to a security threat, suggesting its implementation was for show rather than for practical security benefits. The requirement to divest liquids, often resulting in items being discarded, has become a routine, albeit frustrating, aspect of air travel for many.
