If you're looking for a microcosmic foundation for a fair and just society, imagine being on a cruise ship that is shipwrecked in uncharted waters (I know there are none now, but go with me on this) and that you find yourself one of something like 30 survivors who somehow make their way to a small and isolated island. There's no chance of a quick rescue because nobody knows you're there and there's no record of the island on any maps. So what do you do? Well first you ensure that everyone is sheltered, and you won't last long unless you sort out a food supply and a source of drinking water. Making fire might also be a life saver at night and useful if you plan on cooking any of the meat that you quickly teach yourself to hunt. If all goes well you'll soon have a community that will be protected from the elements and any potentially dangerous wildlife and have enough to eat and drink. If anyone is ill or injured you'd do whatever you could to help them and make them comfortable. If rescue is not on the immediate horizon, you ideally need to get all these things in place before you even think about what to do next.

Now imagine that this is all working well, then one member of that community convinces himself (I'm making him male but he could just as easily be female) that he is somehow more deserving than his fellow survivors and starts taking more than his equal share of food. Let's take it a step further and say that his ego expands to the point where he ends up hoarding more food than he can ever eat simply because he thinks he has a right to do so, with the result that the more vulnerable members of the community are starting to go hungry. Maybe a couple of them even die. Of course, it wouldn't get to this stage. Why? Because the moment this self-important tosser began stealing food, the rest of the community would turn on him and redistribute what he had taken. If he'd been caught secretly hoarding it away to the detriment of the rest of the community, the likelihood is that he'd be punished or even sent out into the jungle and left to fend for himself. If his hoarding resulted in illness or death then there's a fair chance the other survivors would seriously injure or kill him.* Yet in modern western societies we somehow put such people in positions of power and allow them to pass laws that protect themselves, their ungodly gains and those who do likewise from the consequences of such actions.

Leilani Farha meeting residents in Barcelona. Photo: Janice d’Avila

The right to housing is enshrined in a number of human rights agreements, including Article 25 of the Universal Declaration of Human Rights, Article 28 of the Convention of the Rights of Persons with Disabilities, Article 11 of the International Covenant in Economic, Social and Cultural Rights, and Article 16 of the European Social Charter. Yet according to the charity Shelter, over 320,000 people are now homeless in the UK alone, while the number of people in accommodation that would not meet that first quoted document's stipulation that everyone should be entitled to a standard of living adequate for the health and well-being of themselves and their family is now in the millions. It should come as no surprise that the vast majority of the latter are in rented flats or houses owned by amoral capitalists who either have no interest in the welfare of the tenants that made them rich in the first place or openly despise them. Making matters worse is modern phenomenon of ‘gentrification', an innocuous-sounding term for the buying up of whole swathes of previously working-class boroughs by the obscenely wealthy, pushing rents and house prices up to such a level that long-term residents can no longer afford to live there. But there's more. Many of these now expensive homes are not bought for habitation but as investments by distantly located individuals and corporations. This has the dual effect of pricing average-wage workers out of the area and reducing the number of local homes available for habitation. And let's not get started on the further impact on housing availability caused by the rise of Airbnb, which has seen an unprecedented rise in the purchase of second homes by those looking to make a bit of dosh by renting them out to leisure travellers and holidaymakers.

It's the growing and international nature of this issue and the impact it is having on lower and middle-income city dwellers that is the focus of Push, the latest feature documentary from Swedish director Fredrik Gertten. The lynchpin of the film – its central character if you will – is UN Special Rapporteur on the Right to Adequate Housing, Leilani Farha, who is followed by Gertten and his crew as she travels from country to country to investigate the plight of some of those negatively impacted by the above outlined trends. This proves to be both a strength and a partial handicap for the film, providing as it does a useful whistle-stop tour of the sort of problems that this commodification of dwellings is creating at a variety of international locations – including cities in Canada, Britain, Germany, Korea, Chile and Sweden – but it also leaves Gertten with limited time to explore any of them in the sort of depth they really deserve. Having said that, there's only so much you can cover in a 90-minute feature, and to really get to grips with individual cases would require something like a ten-part TV series, and I'd probably still be complaining that there was more to say on an issue that has been dear to my heart for some time.

What the film does do well is make it clear just how widespread the problem is becoming by highlighting, for example, what links a small German bakery's struggle to stay afloat with the plight of a group of beleaguered residents on a Toronto housing estate. Farha's conviction and drive is certainly admirable, but the real stars are those she meets and engages with on her travels. All make their cases eloquently, none more so the survivors of the catastrophic Grenfell Tower fire in London, the memory of which still haunts me to this day and prompted visible shudders of horror when I mentioned it to my sister whilst writing this review. As Farha herself notes at one point, this disaster perfectly encapsulates the social and economic divide that is at the root of the problem, a tower block inhabited by low-income families but located in a borough that is the also the site of some of the world's most expensive houses and where the gap between the richest and poorest is the highest in the country. Lest we forget, 72 people died in the Grenfell fire, more than 70 others were injured and 223 survivors lost their homes, yet nine months after the disaster, when this segment of the film was shot, most had still not been rehoused and no guarantees were being made about the location of any alternative accommodation that might eventually be offered. You can bet your bottom dollar that had the fire taken down a few of the borough's luxury houses, no expense would have been spared to care for any displaced victims.

Local housing activists in Valpaiso, Chile. Photo: Janice d’Avila

As the film progresses, international equity conglomerate Blackstone emerges as a symbol of the shadowy corporate nature of this mass property grab, and a potential centrepiece confrontation is tabled when its representatives agree to have a sit-down meeting with Farha, one that despite relishing the thought of seeing I just knew Gertten's camera would not be allowed into. So even-toned is the film, however, that when the meeting is cancelled at the last minute via a dismissively impersonal email, the sense of frustration and anger I should have felt didn't hit me anything like as strongly as I can't help thinking it should have. It's a moment that highlights an element not present here that I've got used to seeing in such films, a ‘gotcha' moment where Farha or the victims of these corporate shenanigans get to confront those responsible, score a significant victory against them or uncover evidence that is set to have a real future impact. This is further underscored by end credits that roll without a single fact or statistic for us to take away and ponder on, a genre staple that may border on cliché but that continues to deliver some of the best and most thought-provoking parting stings in modern documentary cinema.

Yet I'd still argue that at a time when those in power are using disinformation, propaganda and outright lies to swindle the general public into supporting legislation that will ultimately be harmful to them, we really need films like Push, a well-argued work born out of a sense of injustice that highlights a too-little discussed social issue and concisely outlines the threat it poses to almost anyone whose net worth is not in the millions. It may skip from place to place at a brisk pace and not have the time to dig deep into areas that are just asking to be explored further (Airbnb gets a couple of negative mentions, but its contribution to the issue is never discussed in any detail), but it also makes for a most effective introduction for those unaware of the scale or specifics of what really is a growing international crisis. Thoughtful and sometimes damning analysis is provided by Professor of Sociology at Columbia University Saskia Sassen, Nobel Laureate in Economy Joseph Stiglitz, and journalist and author Roberto Saviano, who still requires round-the-clock police protection after his 2006 book Gomorra exposed the extent to which the business world had been infiltrated by the Italian Comorra crime organisation. It's these three who most effectively signal where this growing problem could ultimately take us, with Sassen highlighting the link between financial deregulation and Pinochet fascism, while Saviano reminds us that, “Tax havens are where criminal capitalism and legal capitalism meet and merge. Mafia organizations were the first to create and facilitate money-laundering mechanisms through tax havens.” Think on that next time Boris Johnson talks about deregulating the financial sector and transforming Britain into a low tax haven for overseas investors.

Ultimately, it's the defiance of the people that these corporate interests seek to displace, those who band together to stage rent strikes or organise squats in empty buildings, and the tireless determination of people like Farha that gives the film an underlying sense of hope, albeit one I find myself struggling to share. As wages stagnate and house prices and rents continue to rise, the gulf between rich and poor is increasing at an exponetial rate and the power grab by the über-wealthy seems presently free to carry on unchecked. The central question asked by the film regarding who will be able to afford to live in cities in the future is a pertinent one that some of us have been asking for some years now. Back in 2015 when I reviewed Pang Ho-cheung's dark socio-political thriller Dream Home, I highlighted the astonishing revelation by Shelter that in the whole of London, a city that is home to 8 million people, only 43 residential houses were identified as being affordable for the average first-time buyer, and we've had five long years of government by multi-millionaires since then. And lest you feel distanced from the problem by virtue of your location, it's worth noting that this is no longer a problem confined to big cities, and that for many years now small coastal communities have seen lifelong residents displaced as cottages built for local habitation are transformed into holiday homes by and for wealthy out-of-towners (an issue central to Mark Jenkin's superb Bait). Greed remains an even more powerful motivator than heroin, and once this corporate property grab has exhausted its metropolitan stash, where do you think it will turn its attention to next? For these companies, every town, every village that has housing is a potential investment opportunity whose only barriers to ownership are the people who currently live in them. Push may only hint at possible solutions to a problem that requires the full engagement of corruption-free governments that genuinely care about the plight of their people (good luck with that), but as an informative call to action it definitely meets director Gertten's mission statement by creating a platform for conversation about a subject that has the potential to impact us all, and for that I salute it.

Push is in UK cinemas from 28 February 2020. www.pushthefilm.com

* In the isolated mountain community that is the subject of Imamura Shōhei's history-inspired The Ballad of Narayama, when a family steals food from the community they are all dragged away to a pit and buried alive.