A German inventor is patenting a password-protection system for gun cartridges, which he claims will make firearms safer by preventing accidental and unauthorised use.

Herbert Meyerle, who now lives in the US, has applied for a patent designed to secure ammunition as well as guns with passwords.

Meyerle describes a method by which a passcode entered into the gun itself would have to match the same passcode stored on the cartridge before the weapon will fire.

The gun would check for matching codes and then allow the instruction to fire by means of a radio signal.

At the point of purchase, cartridges could have a code matching the purchaser's gun written to them.

The gun could then request the code each time it is reloaded, and could automatically lock after a preset time. Biometric security could also be added for extra safety.

Although the patent is being pitched as a safety feature, the proposal received bad press when it appeared on the New Scientist blog.

Many firearms enthusiasts have slammed the idea as overcomplicated and detrimental to the point of having a gun for defensive purposes.