Al-Qaeda explosives 'enduring threat' on planes
4 December 2013 Last updated at 09:12 GMT
Al-Qaeda terrorists in Yemen have previously succeeded three times in smuggling explosives onto planes, including one that was recovered from a cargo plane at East Midlands Airport in 2010, while disguised as a printer.
Commander Richard Walton, head of the Metropolitan Police's Counter Terrorism Command, told the Today programme that such threats "remain very real, very enduring and very serious".
He added that the current government has implemented "a range of measures, both overt and covert… to try and mitigate this threat".
Dr Peter Neumann, terrorism expert at King's College London, noted that Western governments are trying to combat the use of explosive devices on planes across two fronts in particular.
"The first is the intelligence front, recruiting informers within organisations [such as al-Qaeda] … the other is the technological front, trying to develop ever-more sophisticated detectors to detect the scent of explosives in incredibly small particles," he explained to the BBC's security correspondent Frank Gardner.
The number of British airports with full-body security scanners is set to be increased from 10 to 21.
First broadcast on BBC Radio 4's Today programme on Wednesday 4 December 2013.