UK airport security rules: What to know as some airports change 100ml liquid requirements

Many airline passengers say the worst part of any journey is the airport security check. Worldwide, an average of half a million people pass through airport security every hour. Travellers resent the limit on LAGs (liquids, aerosols and gels) in cabin baggage, as well as the obligation to extract electronics such as laptops and tablets from hand luggage.

The liquids rules were introduced hastily worldwide in 2006 as “a temporary measure” to protect against explosives. Despite repeated promises they remain in place.

In 2019 Boris Johnson vowed the rules would be eased at major UK airports by 2022, allowing larger quantities and eliminating the need to have liquids separately scanned. Rishi Sunak’s government then extended that deadline to 1 June 2024.

While some of the UK’s airports complied, at other locations the work was not fast enough to meet the deadline. And in any event, a week after the deadline, progress in aviation security actually went into reverse, with the Department for Transport (DfT) ordering airports with the new equipment to restore the old 100ml limit on LAGs.

There is, though, a degree of improvement: passengers can leave laptops, tablets and liquids inside their cabin baggage where the new scanners are fitted.

The Independent has learnt that the majority of major airports are fully fitted with the expensive new kit.

Simon Calder, former security officer at Gatwick airport and current Independent travel correspondent, explains more.

The list of items that cannot be taken through an airport security checkpoints in carry-on bags has increased over the decades. Prohibitions have evolved in reaction to terrorist attacks – successful and otherwise.

All weapons, whether firearms, knives or explosives, are banned from hand luggage. But there are also strict rules about larger quantities of liquids, aerosols, gels, pastes, lotions and cosmetics, extending even to yoghurt, soft cheese and Creme Eggs.

The UK government says: “If you do take liquids in your hand luggage, at most airports:

It adds that frozen liquids are banned, and warns: “Airport security staff will not let anything through that they consider dangerous - even if it’s normally allowed in hand luggage.”

In August 2006 the aviation industry – and baffled passengers – awoke to find security rules for passengers had tightened overnight. The government announced that it had uncovered a terror plot to blow up transatlantic jets from Heathrow to North America.

The perpetrators aimed to take the ingredients for improvised explosive devices on board a number of aircraft. The ingredients, derived from hydrogen peroxide, were intended to be smuggled aboard in soft drink containers. The plotters aimed to assemble the bombs on board before detonating them and destroying the plane. They were later convicted of offences including conspiracy to murder and conspiracy to cause explosions.

The bosses of Britain’s airlines were called in the early hours of 10 August 2006 to be told their passengers would be banned from carrying anything more than a purse or wallet into an aircraft cabin. Even pens were banned from transatlantic flights, on the grounds that the ink they contained was a liquid.

One concession was made, for nursing mothers: they could take milk for their baby through the checkpoint, but only if they tasted it first in front of security staff to demonstrate it was the real thing.

Baggage systems could not cope with two or three times the normal number of items, and Heathrow airport ground almost to a standstill. Flight networks elsewhere in the UK and Europe were also affected.

Three months later, the rules were eased – but with strict limits that prevail today at most airports.

The 100ml limit was selected as a sufficiently low volume to avoid an on-board threat.

No. The limits were introduced as a “temporary measure” while airport security technology caught up. But progress has been painfully slow.

Even a very modest relaxation of the rules – to allow airport purchases of drinks to be taken through checkpoints in a sealed “security tamper-evident bag” (Steb) – took years to be implemented. Many passengers are still being caught out, losing their expensive airport purchases, because duty-free drinks are not allowed through the airport where they change planes.

Yes. Modern scanners use computed tomography (CT) – the same technology as medical scanners – to analyse the molecular structure of the contents of a passenger’s bag. The machines can detect potential threats and present security officers with a three-dimensional image of the contents.

They can also analyse whether laptops and other electronic equipment present a danger.

At airports where the technology is installed, liquids and laptops no longer have to be removed.

The aim is that security should be enhanced, with more sophisticated assessment of potential threats. The amount of staff time consumed in “secondary searches” should be reduced, allowing officers to spend more time assessing passenger behaviour.

Travellers have a much easier experience: they no longer need deconstruct their cabin bags, and the whole airport process feels much smoother and less stressful.

No. At some airports, LAGs must still be carried within a resealable clear plastic bag with a maximum volume of one litre, and removed for the security check. But at many UK airports with advanced equipment already installed, liquids ancan be left in the passenger’s luggage. These include:

At other key airports, the installation of new generation kit is well under way – but some old tech remains. These include:

On 9 June 2024 airports that had ploughed tens of millions of pounds into meeting the government deadline were abruptly ordered to restore the 100ml limit. At London City and Teesside, for example, the new scanners had been working well for over a year, with passengers understanding

It was not a complete reversal; passengers will still be able to leave liquids, aerosols, gels, etc, in their cabin baggage. They must, though, be in containers of 100ml or less.

It was described at the time by the Department for Transport as a “temporary move” to “enable further improvements to be made to the new checkpoint systems”.

There are two problems. One is mis-identifying many innocuous items in passengers’ baggage as posing a threat.

Sources have told The Independent that harmless liquids such as sunscreen have been misidentified as high-threat substances. Innocuous items such as books placed close to laptops, or bananas, have also triggered alarms.

The converse, and what alarms the aviation security industry, is that dangerous items could be passed as safe.

No. Worldwide, lack of conformity is a key issue for aviation security professionals – and passengers.

At many airports liquids are limited but can stay in the traveller’s bag. Laptops and tablets such as iPads must be removed at some airports in the UK and many other countries, but in some nations they need not be.

The European Union (and wider Schengen Area) has also reverted to the “old” rules at all airports from 1 September 2024, following concerns about the new equipment installed at some airports.

Olivier Jankovec, director general of the airports’ body ACI Europe, said: “Those airports which have been early adopters of this new technology are being heavily penalised both operationally and financially.”

In Israel, procedures are entirely different. The authorities say: “Passengers should arrive three hours prior to departure for the security check procedure.” There is sometimes intense questioning by officials, and laptops must be removed. But liquids are permitted without restriction, except to the US (see below).

The main issue: passengers should not expect aviation security to be the same worldwide – or even UK-wide. At some small Scottish airports including Barra, Campbeltown?and Tiree there have been no security checks since 2017.

While all other nations simply focus on outbound flights, the US imposes a whole set of rules on flights inbound from overseas to American airports – with particular reference to “powder-like substances”. The 100ml rule is also strictly enforced.

The Transportation Security Administration says: “If you are flying from any of the last-point-of-departure airports into the US, you may experience a more extensive screening process and should prepare for additional screening of your property and personal electronic devices.

“Ee encourage you to place powder-like substances over 350 m; in your checked bags. Powders in carry-on baggage may require secondary screening, and powders that cannot be resolved by security officials will be prohibited from the cabin of the aircraft.”

The airports that are collectively investing hundreds of millions of pounds will be seeking a return – and that could include raising fees. But the long-term aim is that new tech should cut staff costs, representing savings for airports.

Willie Walsh, director-general of the International Air Transport Association (Iata) –?representing airlines worldwide – said: “Implementing this technology should not come with a big bill. In fact, simplified processes should deliver significant efficiencies.”

“Speedy deployment should be possible. The technology has already been used successfully and for a long time at various airports across the world with measurable improvements to the passenger experience.”

No. In 2019 Iata described the prevailing security situation as “no longer sustainable”. It has been working with airports for over a decade on a project called “Smart Security”.

Ultimately walk-through metal detectors and security pat-down of many passengers should be eliminated, with technology assessing possible threats more effectively than humans watching screens.

The passenger should be able to walk unchallenged along a corridor flanked by detectors, barely aware that they are being checked.

Checkpoints will still be staffed, but security personnel will be freed up to do what people do best, which is to study the behaviour of passengers and identify “persons of interest” for further investigation.

However, as the reversals at UK and EU airports show, there is a long way to go.