It has been said that terrorism is a zero-sum game. But try telling that to the manufacturers of three dimensional body scanners, the use of which at airports worldwide is set to soar after the failed bombing of a Christmas day flight into Detroit.

In the United Kingdom, however, a proposed "gradual" introduction of devices which take nude photos of their subjects has run afoul of child pornography law, according to British newspaper The Guardian.

"Ministers now face having to exempt under 18s from the scans or face the delays of introducing new legislation to ensure airport security staff do not commit offences under child pornography laws," a Monday report reads.

"A 12-month trial at Manchester airport of scanners which reveal naked images of passengers including their genitalia and breast enlargements, only went ahead last month after under-18s were exempted," it continued.

The high-tech body scanners can detect hidden objects, such as explosives, even when they are concealed by clothing, unlike the metal detectors passengers walk through in airports worldwide to access flight gates.

Airport officials insist that the images are only viewed by a single security official in a location removed from the passengers.

The Netherlands, Britain and Nigeria have announced plans to rapidly deploy the use of full-body scanners at their airports.

In the United States, the scanners are already in use at 19 airports, a practice that could become widespread.

"The US alone has 450 airports with about 2,000 security lanes, which gives an idea of the potential" of the market, said Joe Reiss, a spokesman with American Science and Engineering (ASEI), one of the world's four leading makers of full-body scanners, in an interview with AFP.

The other manufacturers are two US companies, L-3 Communications and Rapiscan Systems, a unit of OSI Systems, and British rival Smiths Detection.

Shares in L-3 gained 3.0 percent between last Thursday and the market close Wednesday in New York, and reached a 14-month high on Tuesday.

Shares in ASEI and OSI leapt 10.5 percent and 26 percent, respectively, over the same period.

According to Reiss, a body scanner costs about 100,000 dollars, a hefty expense compared with the 10,000-dollar price tag of a metal detector portal.

The latest generation of X-ray baggage scanners cost some 150,000 dollars, while those used to screen checked baggage, a larger volume, cost one million dollars.

"We understand the concerns expressed about privacy in relation to the deployment of body scanners," British transportation authorities told The Guardian. "It is vital staff are properly trained and we are developing a code of practice to ensure these concerns are properly taken into account. Existing safeguards also mean those operating scanners are separated from the device, so unable to see the person to whom the image relates, and these anonymous images are deleted immediately."

With AFP