Abstract: A security enclosure includes an access gate comprising at least one rigid barrier which can be retracted or advanced by remotely-actuated power means for opening and closing the gate. A support and drive structure which supports the driven end of the barrier includes upper drive means which provide positive drive connections to an upper surface of the barrier through downward pressure on at least two laterally-separated points and corresponding lower drive means which provide positive drive connections to a lower surface of the barrier and support the barrier on at least two laterally-separated points, with the upper and lower drive means being driven by a common power source and connecting drive means to open and close the gate. Remote switching means are provided to operate the drive means and latch means to open and close the gate. The upper and lower drive means can be rollers driven by belt drives.