Failed attack shows how air security can be subverted
By Gordon Corera
Security correspondent, BBC News
Investigators are continuing to try to urgently establish the origins and details of the latest alleged attempt to bring down a plane as understanding this will be key to getting the right security procedures in place.
Both those seeking to bring down planes and those seeking to stop this happening are constantly adapting to the other side's actions and an incident such as the alleged attempt on an Amsterdam-Detroit flight on 25 December leads to urgent reassessments.
Richard Reid also tried to bring down a transatlantic jet
Britain's Joint Terrorism Analysis Centre (JTAC), housed with MI5, assesses and analyses all counter-terrorism intelligence from home and overseas and is liaising closely with its US equivalent, the National Counterterrorism Centre.
JTAC has already issued a number of reports relevant to the investigation to its customers in the British government, especially those dealing with transport security.
Even though the alleged bomber spent a number of years in the UK, so far it does not look as if the UK was the centre of any conspiracy.
Liquid bomb plot
Umar Farouk Abdulmutallab spent around three years in the UK but is believed to have left shortly after his degree finished in 2008.
He was denied a visa to return to the UK but it is thought this was because of concerns over whether the college he was applying to study at was legitimate, rather than because of concerns over him as an individual.
According to some reports, he may have only returned to Nigeria the day before getting on his flight to the US on Christmas Day, and it is still suspected that he received the device and instructions from Yemen. He has told investigators at one point he was instructed by al-Qaeda.
If this is true, it looks like just the latest in a series of attempts to find new ways of evading security measures at airports and elsewhere.
This was seen with the shoe-bomber Richard Reid in late 2001 and later with the liquid bomb plot of 2006.
More recently there was an attempt on the life of a Saudi prince using some kind of "body bomb" to evade security checks.
That attack was also believed to have originated from Yemen and there are concerns that at least one innovative bomb-maker may be operating in the lawless parts of the country.
Yemen looks increasingly strategically important in the struggle against al-Qaeda.
This may be a result of the pressure on al-Qaeda's leadership in Pakistan and Afghanistan thanks to strikes by CIA predator drones. The first drone strike occurred in Yemen late 2002.
The latest alleged plane attempt looks to have involved explosives moulded to the body in order to evade detection by airport scanners.
It is believed that only a faulty fuse stopped it exploding as intended.
This is similar to the experience of Richard Reid, who managed to get his device past security even though it then failed to detonate.
Analysts will be working hard to understand whether any new device can be detected by current airport security procedures, or whether new systems will need to be put in place.
The concern will be that otherwise those seeking to innovate may learn their lessons and get a working device past security next time.
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