Is this the beginning of the end for air travel liquid restrictions?

It has been years in the making but a new scanner could soon be in place across UK airports that will free travellers from the hassle of having to remove gadgets and liquids from their hand luggage when going through security.

Back in 2016 Telegraph Travel first reported that new equipment using CT (computerised tomography) technology was being tested at airports in the US, beginning in conjunction with American Airlines at Phoenix, Arizona.

Since then the X-ray scanners, working in the same way as CAT scanners used in hospitals, have moved closer to home with London Heathrow this week said to be running a “small number” of trials that would last between six and 12 months. The scanners, which can detect explosives, allow security staff to assess items - including liquids - without needing them to be removed from bags.

A spokesperson for Heathrow said: “We continue to look at new technologies that can both improve the passenger experience and strengthen our security.”

The Department for Transport said if the trials were successful “this could lead in future to passengers no longer needing to remove items from hand luggage for screening”.

Luton Airport tested a similar CT scanner last year that would allow passengers to take carry-on luggage through security without removing liquids. A spokesperson for the airport said the results of the trial were handed to the Department for Transport.

What are the current rules?

All liquids, including drinks, cosmestics and toiletries, sprays, toothpaste, gels and semi-liquid foods such as soup, jam and honey, must be in containers no larger than 100ml, which must then be placed in a single, transparent, resealable plastic bag, which in turn can only hold a litre. 

“Contents must fit comfortably inside the bag so it can be sealed,” states Government regulations. “You're limited to one plastic bag per person.”

Liquids of 100ml or less cannot be taken on board if they are in containers greater than 100ml. For example, if you have finished three quarters of a 200ml jar of your favourite Slovenian honey, you still will not be able to take it in your hand luggage. Only some medicines, baby food and items of special dietary requirement are exempt. 

The latest 3D scanners have already been tested at Amsterdam Schiphol and John F Kennedy in New York, and are already used on hold luggage at a number of airports.

It is not yet clear where in Heathrow the tests will take place and the DfT told the Guardian passengers should still expect to be asked to remove items from their bags.

Why was the ban in introduced in the first place?

Introduced by the UK government in August 2006, the legislation was in response to a foiled terror plot to blow up flights between the UK and North America.

Three British men were convicted for conspiring to assemble improvised explosive devices on board transatlantic jets – devices containing a liquid derived from hydrogen peroxide – and detonate them above the Atlantic, killing all those onboard.

The Government, along with governments around the world, responded to the plot by introducing strict rules prohibiting passengers from taking little more than their wallets through security.

Chaos ensued; security checkpoints were overwhelmed, baggage systems were swamped and airports ground to a near standstill. Things got so bad that British Airways was forced to cancel more than 1,500 flights.

Will the new technology spell the end of the liquid ban?

There is no word on whether the introduction of new scanners would lead to a change in the restrictions on liquids, though in theory if the technology can alert staff to threats in 100ml of liquids, it could do so in any volume. 

But that principle has been so ever since 2006.

“I would understand more if there was a total ban than a restriction,” said Philip Baum, editor of Aviation Security International, in an interview with Telegraph Travel. “It just demonstrates that governments, and not just the UK government, but governments around the world, want to have tick-box security – they don’t want screeners to apply their common sense.”

Baum told the Guardian this week that the new technology “is the beginning of the end of the liquid ban”, though there is nothing to suggest that is the case. 

Baum is not alone in his criticism of the limits (he says would-be terrorists could “buddy up” with others to mix explosive liquids in a bigger bottle bought from duty free). According to the Adam Smith Institute, one of the world’s leading think tanks, current restrictions would not prevent determined terrorists from getting liquid explosives through airport security. “Indeed, the very basis of the restrictions seem weak,” it said, in a blog post.

Then what is the point of the new scanners?

Technology focussed on smoothing the passenger journey through airport security has been in the pipeline in 2016 when Lord Ahmad of Wimbledon, then a minister for transport, said: “The UK has some of the strictest security measures in the world, and we are leading the way in using new technologies to improve security screening at airports, as well as improving the passenger experience.”

At the time Jeffrey Price, a professor of Aviation and Aerospace Science at Metropolitan State University in Denver, said: “The machines have to be adaptable to new threats to the extent possible. Every time there is a new type of threat we can't be putting another box of technology into the footprint of a checkpoint.”

The EU has been keen to lift the restrictions for some time, but its deadline for doing so has been put back several times.

At one point it looked as if the 100ml limit could be enlarged. Now allowing small amounts of liquids to be left in cabin luggage, rather than placed in a clear plastic bag and scanned separately, appears a more likely option.

Airlines have made clear in the past that there would have to be a consistent approach across all airports before the rules are eased, warning that different policies would create chaos.

At a glance | How to spot a terrorist, according to US airport security

What do security experts think?

One of the accusations levelled at airport security regulators - the Department for Transport is in charge of regulations in the UK - is that they react to terror incidents in a knee-jerk manner.

In March last year when the ban on laptops and electronic devices on flights between the UK and six Muslim-majority countries was introduced, Philip Baum labelled it “bizarre”, lacking common sense and only adding to the inconvenience of passengers.

He believes that “profiling” is a more effective security tool. “We focus so much on the search for prohibited items when we really, really should be focusing on negative intent,” he said.

“Until we start to empower screeners and recruit the type of screeners that can actually use their common sense we will continue with this security theatre.

“It’s about making sensible decisions that are based on some form of risk assessment, which is why I’m so passionate about behaviour analyses and passenger profiling.”

26 spectacular airports you must land at in your lifetime

Has security changed in other ways of late?

Despite the possible relaxation of restrictions on liquids, it emerged earlier this month that the Government was considering 12 ounce limits on powders, such as coffee, make-up and spices, being taken in hand luggage. The same rules are being put into practise in the US, Australia and New Zealand.

The laptop ban introduced last year on flights to a number on Muslim-majority countries, including Turkey, Egypt and Tunisia, has now been lifted.