Cameras are "locked" to the Editor Level of the approving editor. An editor must be at least the same level as the approving editor to delete an approved camera. An unapproved camera does not have this restriction.
Cameras can be removed in the same manner as other map elements in the Editor -- select the camera and press the trash can icon in the menu bar.
Once deleted, the map tiles must be updated for this change to propagate out to the users. However, the deletion itself will not trigger the tile update, so make sure that some other edit to the nearby roads is made so that the tile will be sure to update.
Be sure you have confirmed the camera is not present and if there are multiple cameras in the area, be sure you are deleting the correct one.
* [[Speed_and_Traffic_Light_Enforcement_Cameras_(United_Kingdom)|United Kingdom]]