There is provided a locking system having a lock bar and a lock cylinder, where the lock cylinder comprises an outer tube, an inner tube and securing means. The inner tube is placed inside the outer tube and has an opening for receiving a part of the lock bar, and the inner tube can rotate between a first and a second position relative to the outer tube corresponding to open and locked position of the locking system. The outer tube, the inner tube, the securing means and the lock bar are dimensioned so that when the inner tube is in the first position relative to the outer tube, then the securing means are in engagement with the outer tube and the inner tube, and the lock bar can be brought in and out of the inner tube, and when the inner tube is in the second position relative to the outer tube, then the securing means are in engagement with the inner tube and the lock bar, whereby the lock bar is securely locked to the inner tube, while at the same time the lock bar and the inner tube can rotate relative to each other. It is preferred that the securing means is made up of a number of locking balls.