Yes, as of 2026, you are absolutely permitted to take crisps (potato chips) in your hand luggage when flying from UK airports. Under current UK Civil Aviation Authority (CAA) security rules, crisps are classified as solid food, which is not subject to the 100ml liquid restriction. While many UK airports have upgraded to CT scanners that allow liquids to stay in bags, solid snacks like crisps have never been an issue. However, be aware that the air pressure in the cabin can cause sealed bags of crisps to expand and occasionally "pop" during flight. Security officers may also ask you to remove large quantities of snacks from your bag for separate X-ray screening if they appear "dense" on the monitor. Once you clear security, you can eat them freely, though it is considered polite travel etiquette to avoid particularly "aromatic" or noisy snacks during the flight to remain mindful of your fellow passengers.