A locking device (e.g. for use as a vehicle steering lock) has a locking bolt 3 operable by a plastic card encoded key inserted into chamber 10. A latch (not shown) is provided to retain the locking bolt in a locked position (shown) until a sensor 16 reads and verifies information stored on the encoded key as the key is inserted. A solenoid then disengages the catch to allow the key to operate the locking bolt by pushing a member 9 which causes a cam 6 to rotate on axis 5 and engage a bolt projection 7. <IMAGE>
