Blocking device for blocking an essential component of a motor vehicle, particularly for blocking a steering column of a motor vehicle

The device (1) has a lock bolt (5) movable in a stroke axis (6) between a locking position and a release position for locking and releasing a function-substantial component. The lock bolt is blocked by a locking element in the locking position, and a support arm is provided for retaining a locking element from interference in a form closure geometry. A housing (3) comprises a housing part with a safety-relevant housing region, and the support arm is partially arranged within the safety-relevant housing region.