Signum Services Limited, is also the UK Government's official agency entitled 'Security Seal Testing Authority' for the testing of security seals.
The seals themselves, from manufacturers all over the world, are sent to the Authority and are then strenuously tested by an engineer to ensure that they cannot be unsealed without leaving telltale signs of interference. Having undergone these stringent tests, only those that pass receive the approval of the UK Customs and Excise, a qualification highly sought after by manufacturers as a selling point; no other country in the world requires seals to be tested in this way.
Consequently, over the years, the quality of seals has risen with a far greater proportion being impregnable without leaving signs of tampering.
The result is that thieves wanting to steal all or some of the cargo from a sealed container and wishing to leave the seal intact are resorting to other means to open the doors.
If, on receipt of a container at the consignee's premises, the cargo is missing but the original security seal is in place and intact, there is a simple explanation and the explanation is always simple - cargo cannot magically disappear through the walls of a steel container. If the seal is of good quality and is one which cannot be opened without leaving evidence, and the container bears no evidence of a hole having been cut in its metal work then the only way entry has been gained is by tampering with the door mechanism.
This is becoming a more frequent problem and usually occurs in one of two ways: either by removing the handle lock set complete, with the seal in place, from the right hand container door by cutting off the rivets which hold it on (upper photo), or by cutting off the rivet which holds the handle in the locking bar handle hub (lower photo).
Thieves who adopt either of these two methods can then open the doors of the box and remove the cargo. The door is then secured by replacing the missing rivets with bolts, the original seal being undisturbed.
All this is possible because the entire door locking mechanism and both parts of the seal bracket are fixed to the door itself and no part of them to the body of the container.
Cable and barrier or bar seals combat the problem by being looped or hooked around the locking bars of both doors. These seals of course cost extra money. However, boxes are now being manufactured with one part of the seal bracket being at the foot of the locking bar, on the cam on the right hand door and the second part of the bracket welded to the container itself on the bottom of the box on the door sill.
The seal therefore, when in place, secures the locking bar to the container itself. The result is that no bolts, rivets or parts of the locking mechanism can be removed enabling the container to be opened leaving the seal intact. If the doors have been opened, the seal must have been breached. As containers are renewed and replaced over the years, they should be replaced with those bearing the seal brackets at the bottom of the locking bar and on the door sill.