By Dominic Casciani
Prime Minister Gordon Brown has ordered the introduction of full body scanners at British airports in the wake of the attempted plane attack on Christmas Day over Detroit. What measures are already taken to screen air travellers in and out of the UK?
PASSENGER DATA CHECKS
The entire system of passenger checks is changing in the UK with the introduction of an electronic scheme designed to count people in and out of the UK.
UK E-BORDER SYSTEM
Scheme first piloted in 2004 but ramped up this spring
100 million journey processed
4,000 arrests made
Aims to cover 65% of all journeys by end of 2009
Aims to cover 95% of all journeys by end of 2010
Hopes to be fully operational by March 2014
The £1.2bn project, known as e-Borders, is an exceptionally complex and challenging programme to completely modernise what the UK Border Agency knows about passengers.
The previous largely paper-based system was scrapped progressively by Conservative and Labour governments because it had become unworkable.
E-Borders will collect information on everyone entering or leaving the UK. Much of the information has to be collected by the carriers, mostly airlines, and passed on to the authorities just before departure.
The minimum requirement is each passenger's name and all the details in their passport. But the UK Border Agency has the right to ask the carrier for much more information, including their e-mail address, credit card number, car registration number and the name of the person who made the reservation. This can then be checked against immigration, customs and police watch-lists.
That information will then be used to better understand who is coming and going and why - but also to improve the means of identifying people who are a threat, criminal or otherwise.
The Home Office is promising that the scheme will be efficient - but many travel firms and carriers remain sceptical, predicting chaos as the system is rolled out over the next four years.
The e-Borders scheme is, in fact, part of a bigger worldwide shift in how government agencies manage and share passenger data. Some countries have already introduced passports that hold biometric data on a chip. And the UK is among a number of countries looking at wider use of iris-recognition systems to speed up entry and exit.
PASSENGER WATCH LISTS
The UK operates a number of "watch lists" set up to alert the security services to particular individuals.
Umar Farouk Abdulmutallab, the man charged with attempting to blow up the Detroit-bound airliner, was banned from entering Britain.
Umar Farouk Abdulmutallab was refused a visa
He had been refused a multi-entry student visa and placed on an immigration watch-list last May. His refusal was not on national security grounds but because he had been tagged as a potential illegal immigrant because he had applied to study at a bogus college - a popular route for unauthorised entry.
This ban would have prevented him from entering the UK - but not from passing through an airport, if he had applied for and been granted a specific transit visa. This may at first appear contradictory, but the reality of international travel is that there are a string of major hub airports, such as Heathrow, Schiphol, Singapore and Frankfurt, which act as the waypoints for people going on to other continents - and the national authorities need to manage that flow of these people without bringing the global system to a halt.
US officials have said Mr Abdulmutallab was put on one of their "long" watch-lists but was not banned from travelling. His name was on a US security watch-list of more than 500,000, known as
Terrorist Identities Datamart Environment (Tide).
But there was apparently not enough information to include his name on the smaller Terrorist Screening Data Base (TSDB), which includes a no-fly list. This meant no concerns were raised when he bought his ticket to the US and had his passport and visa scanned.
The UK government excludes people from entering on the grounds that they have been engaging in "unacceptable behaviour" - 105 people have been excluded in this way, a small number of whom have been publicly named by the Home Office.
The list includes 73 people excluded for "fomenting, justifying or glorifying terrorist violence", two people excluded for "seeking to provoke others to terrorist acts", 21 individuals excluded for "fomenting other serious criminal activity or seeking to provoke others to serious criminal acts"; and nine people excluded for "fostering hatred which might lead to inter-community violence in the UK".
As any passenger knows, customs are a fact of life for anyone arriving from abroad. The British system has changed massively thanks to the European Union - with freedom of movement and trade for its citizens meaning very few checks for many passengers. That doesn't mean the customs officials have disappeared.
Heathrow has a massive customs operation, led from a huge computer control room where officers are using their professional experience and intelligence to work out which flights to target and which cargo to inspect.
This kind of work can feel like hunting for a needle in a haystack. There are more than 200 major "freight sheds" that are fed by flights in and out of Heathrow. Any of these can be subject to customs and excise operations.
Freight operations are primarily focused on looking for drugs - officers identify cargo they want to inspect and then break it open to see if they were right. Some of the job is guesswork - but successes also come from knowing which flights are used by smugglers.
When it comes to passengers, officers identify suspects thanks to prior intelligence or tell-tale signs that something is up. It's at this stage that customs officials deploy some of the technology now being proposed for checking passengers who are leaving.
No liquid in containers larger than 100ml - excluding essential medicines
"Liquid" includes drinks, syrups, creams, mascara, gels and pastes
All items should go in a clear 20cm square plastic bag
All major British airports now have two machines designed to spot smuggled drugs as passengers enter the UK. The first, is a low-dose x-ray machine that looks for the "swallowers and stuffers". In other words, it will spot the wrap of heroin sitting in the stomach. This has been used on suspected drug mules arriving at Heathrow since 2006.
The second machine is the milimetric-wave camera, deployed to Heathrow in October 2008. This bounces a radiowave off the body and, thanks to its frequency, penetrates clothing and provides an image of the skin and surrounding tissue. The resulting image is shows the body and can expose items hidden in clothing. For instance, drugs or explosives carefully hidden in the lining of clothing could be, theoretically, identifiable. Critics say that it's like a virtual strip search and have raised privacy issues about its use. It is a version of this machine that the government wants to introduce for departing passengers.
Restrictions are still in place at UK airports on liquids that can be carried on board planes, after the discovery three years ago of a plot to blow up transatlantic airliners. Some European airports are trialling scanners capable of detecting liquid explosives, which may eventually remove the need for restrictions. One company linked to Durham University has produced its own device for scanning bottles quickly.
FULL BODY SCANNERS
The Prime Minister has now pledged to introduce full body scanners at British airports. While the UK Border Agency has the machines to detect drugs, they have only been trialled between 2004 and 2008 for departures from Manchester and Heathrow. The first body scanners for departing passengers will be introduced at Heathrow before February, the Home Secretary has said. The government has also pledged to draw up special rules on how the machines are used to protect people's privacy.
Technology exists to scan under clothes but there are privacy issues
Amsterdam's Schiphol airport already has these devices - but not everyone has to pass through them. Umar Farouk Abdulmutallab was security screened on his arrival at the airport from Lagos, as were all passengers - but that check included a metal detection gate - and not the full body scan. The device he was carrying was designed to go undetected at a metal detection gate.
Supporters of the body scanner approach argue that it would remove the need for a largely symbolic "pat-down" search.
Aviation security expert Chris Yates said: "There are good security personnel and bad security personnel in our airports and I've seen some very awful examples of the pat down.
"If it's done effectively, yes, you can do a proper examination of somebody and pretty much determine whether they are hiding something.
"But at the end of the shift, on a bad day at work, the security guard is just wanting to get home. I would prefer to see technology doing the electronic pat down, if you will, than a person doing it."
But the jury is out on whether they would identify all threats. Conservative MP Ben Wallace was formerly a director at QinetiQ, the UK's defence research body.
"These scanners are not the magic bullet that's suddenly going to solve the problem. The problem's been out there for two years. The Government's been underfunding defence research which could have helped solve the problem and now we're left in a position where the PM seems to think a couple of scanners are going to make a difference."
Pentaerythritol tetranitrate (PETN) - the type of explosive allegedly being carried by Mr Abdulmutallab - could have been detected by swabbing passengers' bags for traces of explosives.
This method is used at major airports, including Schiphol, but only on passengers who attract special scrutiny.
"Puffer" machines that blow air on a passenger to collect residue may also detect such material - and trained bomb sniffer dogs may also have worked.
Some experts argue that instead of forcing all passengers through full body screening or swabbing, which would increase costs and lead to unacceptable delays, behavioural experts should be used to identify individuals for special screening. BAA, which runs many of the UK's major airports, is now training some of its staff to spot the warning signs of a potential suspect.
This already happens at some US airports and, according to security experts, Schiphol airport. There are calls for them to be deployed in the UK but concerns have been raised about racial profiling.