Didn't some Sovietski submarine once sail past the Rock of Gibraltar with what looked like a pair of Atolls atop the conning tower?
Later assumed to be spook-bait, once the MPA force had recovered from the surprise of something prepared to surface and fire back?
Groundcrew-created spotter-bait at TWU one year during an 'At Home Day' included a spoof 'Sidewinder modification programme timetable' in one of the Hunter engineering offices through whose windows the little aluminium stepladder and camouflage waistcoat brigade would poke their lenses..
