The Electrocannon is a hybrid device. While conventional cannons use an explosive charge to launch a projectile, and devices such as Gauss guns, railguns and disc launchers use electromagnetic acceleration, the Electrocannon uses an electrical discharge through a conductive liquid to generate an explosion which in turn launches the projectile.
This electrocannon was built as a proof of concept, but only briefly tested due to a unanticipated success. On first fireing, the team expected a modest 'pop' and for the projectile to launch a meter into the air. Instead the force of the exposion deformed the barrel and blew the rear of the cannon off. The projectile itsself was never recovered, nor were those used in the following tests with a more durable barrel. Even with a 250FPS camera it was not possible to film the projectile leaving the barrel.
After some consideration of UK firearms laws and the ambiguous status of this device, it was decided to discontinue this line of experimentation.