There are a number of 3D-printed gun designs now freely available on the web.
These guns are capable of killing, and accurately mimic real-life weapons.
Since they are made of plastic and not metal means they can be taken through metal detectors without being picked up.
In 2013, the Mail On Sunday exposed the international security risk posed by a gun that can be easily made with new 3D printers.
They built a weapon, which is capable of firing a live round, from blueprints available on the internet – then smuggled it on to a packed Eurostar train.
Gun control advocates argue that the 3D printed guns could go undetected by metal detectors. However, to be legal, they have to contain detectable metal parts
Two reporters passed completely unchallenged through strict airport-style security to carry the gun on to a London to Paris service in the weekend rush-hour, alongside hundreds of unsuspecting travellers.
The pistol, capable of firing a deadly 0.38-calibre bullet, was produced in under 36 hours using a revolutionary £1,700 machine to ‘print’ its components.
And because all the parts are plastic, they did not trigger the metal detectors all Euro-star passengers must pass through.
In order to be considered legal, the guns must contain detectable metal parts.