Blocking element, particularly for a gate used as a checkpoint

A blocking element for a gate used as a checkpoint includes a housing having a height, a support having a second height and arranged in the housing, a horizontally directed pivot axis furnished on the support, and a pair of blocking vanes each of which are in a form of a circle sector, wherein the pair of blocking vanes are mounted, by way of a tapering sector inner side of the blocking vanes and such that the blocking vanes can pivot about the horizontally directed pivot axis. A drive motor is connected to the blocking vanes on the pivot axis, wherein the drive motor in response to a signal, slides one of the blocking vanes into the other in a telescopic manner from a position which blocks a passage of the gate into a position, which opens the passage of the gate, and wherein the blocking vanes can be drawn apart from one another in order to again block the passage of the gate.