With spoilers!

So.

It’s 2120 or something on Planet Earth. Only two habitable zones remain: the United Federation of Britain is the British Isles and some of near-Northern Europe. The Colony is the entire continent of Australia. Every other spot on the planet has been reduced to an uninhabitable toxic wasteland. The UFB is where the remaining ruling classes of society live (our Eloi in this particular analogy). The Morlock working classes are consigned to living in the Colony, an overcrowded, over Asianised hellhole lifted straight from Bladerunner and given a shot of Avatar and a Soylent Green chaser.
Colonists are permitted to work in the UFB and travel there via The Fall, a 17-minute elevator ride through the core of the earth. Hey! There’s a Palestine-Israel dynamic here. This could be interesting.
Doug and Lori live in their pokely lil apartment in the Colony. But hey! They have love (and Lori’s structurally perfect buns) to see them through.
Things are not well in the UFB. Terrorist leader Matthias is conducting a bombing campaign in the UFB in support of Colony independence. Go easy on the Avatar depth-charges there, Buddy!

So a bomb goes off in on the London monorail. The emergency services leap into action and call all first responders in. Cue Lori, a paramedic. She has to get dressed quickly and make tracks to catch the 6:30 Fall to get to the scene. Riiight – all emergency personal for the UFB are stationed at least 10,000 miles and 60 minutes away. That’s joined-up thinking.
After, Doug gets ready for his own job in the UFB. He works on the assembly line that makes Synthetic cops, a type of Stormtrooper automaton, though SynthCops can shoot straight, are bulletproof and rather more nimble and co-ordinated. They are also comprised of classified military tech and therefore vulnerable to industrial sabotage. Riiight – instead of having Synths make other Synths, the UFB chooses to use humans from the uppity hothouse of dissatisfaction and rebellion that is the Colony.
Highjinks ensue. Doug goes spazzy, realizes he might be a covert rebel agent and goes on the run to the UFB. He collects a stash of emergency cash, the notes adorned with the face of one Barak Obama. Riiight – the USA no longer exists and the United Federation of BRITAIN is the sole superpower yet the currency carries the kisser of POTUS #44.
Doug realizes he is actually a former UFB agent turned rebel sympathizer – Hauser. He meets up with his old flame from Rebe HQ and she takes him to meet Matthias via a trip on the old London Underground into the toxic zone where they have to don gas masks to enter safely. Riiight – the toxic zone actually encroaches into the UFB as far south as Edgeware and it’s airborne yet only some 20 miles away, it’s blue skies and candyfloss in central London.
As for 22nd Century transportation; you have both anti-grav cars that ride on a suspended maglift system of floating roads yet on the ground people are still driving Mini-Coopers with real wheels, observing traffic lights and taking ye old London Red bus if you want to go old skool.
It all ends badly for UFB Chancellor Cohaagen when he leads an army of Synthsoldiers to the Colony on the Fall (because when you want to appear badass, you put on a bulletproof vest and join your troops in a confined space heading to enemy territory (who know you’re coming btw) by the only entry point available (a hole in the ground)). Quaid foils the invasion and Lori gets a bullet in the (Not the buns! Not the buns!) the brain (Thank God!) The Colony is now safe from further aggression because even though the Fall was destroyed, the UFB surely won’t use the considerable airpower at their disposal (Troop transport aircraft? Naw, let’s take the elevator shaft. Decisions-Decisions) for a second go. Riiight?
Oh – at some point, when Doug realizes he is not actually who he thought he was, Lori reveals herself to be a fake-wife babysitting him and his 7 years of fake memories. “Deep down, did you really believe someone like me would marry someone like you?” she taunts him. Hey! He’s Colin Farrell and she used to date Volturi leader Aro but left him to hitch up with some director guy who told her he would cherish her career by helming her in such beauts as Underworld, Underworld: Evolution and now Total Recall. That’s Colin Farrell, crazy bitch! Now, flex those magnificent buns gratefully like a good girl.