Author: Becca Stewart,
Threat Analyst &
Calum Ronald, Senior Risk Consultant
Read Time: 3 minutes
As of March 2023, Teesside airport and London City airport have become the first UK airports to remove the 100ml limitation on liquids carried in hand baggage on departing flights.[1] The 100ml limit has been in place since 2006 and was introduced following a foiled al-Qa’ida terrorist plot to target transatlantic flights using liquid explosives disguised as soft drinks.
The news comes following the Department for Transport’s (DfT) decision in December 2022 to overhaul airport security measures.[2] DfT has set a deadline of June 2024 for all large UK airports to upgrade their security scanners to Computerised Tomography (CT) scanners which will produce high resolution 3D scans of passengers’ belongings, allowing staff to view and identify every item inside the baggage. The CT scanners are better equipped to detect suspicious liquids within passengers’ hand luggage.
The new liquid limit following the transition to CT scanners will be two litres, and liquids will no longer need to be stored in clear plastic bags. There will also no longer be a need to remove liquids, laptops, or electronics from bags before scanning due to the quality of the scans produced by the new scanners. The change is expected to reduce queuing times and speed up airport security processes.
Whilst some other countries are also introducing CT scanners in airports, such as in Schiphol airport in Amsterdam, there is currently no international deadline for this and the presence of CT scanners does not guarantee a change to the 100ml limitation. Passengers will need to be aware that the destination they are travelling to may not have these scanners in place, and therefore, the 100ml liquid limitation and plastic bag requirement may still be in place for their return journey to the UK.
Assessment
Aircraft
- Due to the symbolic value of targeting an aircraft, as a result of the 11 September 2001 attacks in New York, it is almost certain that terrorist actors in the UK maintain the intent to target aircraft in a number of ways including Improvised Explosive Devices, Hijacking, and Bladed Weapons.
- It is unlikely that any terrorist actor would be able successfully to conduct an attack on a commercial aircraft in the UK in the medium term given the stringent security measures in place to access airside areas in airports.
Airports
- Due to its status as critical national infrastructure, it is almost certain that terrorist actors have the intent to target UK airports in a terrorist attack.
- There is a realistic possibility that terrorist actors in the UK could have the capability to conduct a terrorist attack targeting a UK airport.
- It is highly likely that any attack at a UK airport would be conducted against landside areas which are publicly accessible and subject to less security mitigation than airside areas.
- It is highly likely that a terrorist attack targeting landside areas of an airport would use low sophistication tactics, such as bladed or blunt-force weapons, vehicle-as-a-weapon, or fire-as-a-weapon:
> 2007 – Glasgow – Glasgow airport was targeted in a terrorist attack using a vehicle-as-a-weapon and fire-as-a-weapon. A Jeep Cherokee containing petrol containers and several propane gas canisters was driven into the glass doors of the airport.
Risk Mitigation
- Removing liquid restrictions reflects an improvement in security screening equipment, rather than any response to a change in the threat from terrorism.
- Replacing conventional X-Ray machines currently used at airports across the UK to screen luggage, with CT 3D imaging technology and threat detection AI, will provide improved threat detection capability.
- Scanning of luggage will continue to operate alongside comprehensive person screening, such as X-Ray and Millimetric Wave body scans, to provide assurance for detection of any prohibited / threat items on a person. Removing liquid restrictions reflects an improvement in security screening equipment, rather than any response to a change in the threat from terrorism.
Intelligence Cut-Off Date: 22 March 2023
PHIA Scale
The “Probability Yardstick” (below) is a standardised instrument used to provide professional intelligence assessments. Judgements made using the yardstick are relative and reflect the analyst’s confidence in their findings and assessments.
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- Almost Certain: An event is assessed to have a greater than 90% chance of occurring.
- Highly Likely: An event is assessed to have a 76% to 90% chance of occurring.
- Likely: An event is assessed to have a 55% to 75% chance of occurring.
- Realistic Possibility: An event is assessed to have a 40% to 54% chance of occurring.
- Unlikely: An event is assessed to have a 25% to 39% chance of occurring.
- Highly Unlikely: An event is assessed to have an 10% to 24% chance of occurring.
- Remote Chance: An event is assessed to have a less than 10% chance of occurring.
End Notes
[1] Teesside Airport is UK’s First to Scrap 100ml Liquid Security Limit – Teesside International Airport; London City Airport is scrapping the 100ml liquids rule in time for the Easter holidays | CN Traveller
[2] Passengers to benefit from biggest shake-up of airport security rules in decades – GOV.UK (www.gov.uk)
[3] Schiphol the first major airport to switch to CT scans
Threat Analyst &
Calum Ronald, Senior Risk Consultant