I am not saying that that scenario is completely implausible, particularly if it were a Tory Government keen to stay in power by removing a lot of Labour constituencies. What makes the movie singularly laughable is that it is a movie with not one, but three, aspiring Dark Lords.
There's the embittered scientist who has decided that those who have survived through immunity are a racially pure remnant who should live in fantasy Middle Ages forever, something not made more plausible by the fact he is played by Malcolm McDowell. There is his renegade son Sol, who is your standard rock star fire-juggling mutant cannibal punk. And there is the eminence gris of the British Government, who plans to reduce the surplus population - as Scrooge would put it - and then pose as a hero with the cure.
And they all make the very serious mistake of choosing to fuck with our supercool one-eyed action heroine, who is played by Rhona Mitra, who was mad evil Kit in Nip/Tuck, and is someone you really should not mess with. Bullet in the brain first time you meet her, don't explain your master plan in front of her, don't think that putting her unarmed in an arena with a heavily armoured man with a mace, a spear and a sword is going to have any ending that you will enjoy.
None of these people ever watch this sort of movie, which I suppose is plausible during an Apocalypse; none of them can see a Chosen One coming down the track.
I mean, she has the full set - she is an orphan, a foreigner, she has a major body-part missing (and replaced with a cyborg eye with a recording facility); she even has Bob Hoskins as a mentor. Chosen one, definitely.
The down side of what is - I still maintain - a seriously crappy movie is that it has a major piece of Fail, in the shape of gallant soldier Adrian Lester who ends up sacrificing himself for the greater good as characters played by non-white actors have down the years.
It also cooks Sean Pertwee - an actor who should probably avoid being in Neil Marshall films because terrible things happen to him.
At the end, our heroine does something so cool that it makes no sense except in terms of cool - but it really is pretty cool...