I saw this movie on TV in the mid to late 90s. I'm not sure exactly how old it is but it's colour and I would guess 80s or 90s. A plane crashes on an uninhabited island due to some sort of global apocalypse or war. The survivors include (but may not be limited to; can't remember) an older military guy, a gay couple, a single guy who might have been French, an older (post-menopause) woman, and a young, attractive woman. I don't remember the full or correct sequence of events, but the following things happen:
-The old military guy (who has a gun) becomes more and more autocratic.
-The group decide (possibly not unanimously) that they must repopulate the world and the young woman must choose a mate or she will be forced. She chooses the possibly French guy.
-During a group argument on the beach the old military guy shoots one of the gay couple in the head. He was consistently homophobic but the killing might have been to show dominance as I think the rest of the group started to turn against him.
-The old military guy sets himself up in a jungle fort protected by traps. At some point towards the end, somebody, perhaps the French guy or perhaps the second gay guy, falls into one of them which is like an elephant trap; a pit with sharpened pikes at the bottom.
-Over the course of the movie everybody is killed off except for the two women. One of the final scenes is the two of them on the beach.
I cannot say for sure, but I think the movie might be British or Australian. A friend of mine who had also seen it (but didn't know the name either) said the old military guy was played by "that old guy that plays British officers in old-timey films". I'm not sure who he meant and he was unable to clarify. Not the best clue but for what it's worth...
Movies it isn't: After The Dark (aka The Philosophers) (2013), Lord Of The Flies (1963), Lord Of The Flies (1990).