Describing Ken Loach is a challenge: he exudes a rather ethereal aura but is also clearly very grounded. In a talk at his old college – he read law at St Peter’s – Loach speaks softly but with such eloquence and dignity that you want to applaud his every comment. Yet in person he is utterly inconspicuous. Small, lean and notably humble, if he were not ‘Ken Loach’ he could be any college alumnus returning after fifty years.

During his time at Oxford Loach admits that he focused entirely on acting, the profession he thought he wanted to pursue. There was one year, he claims, where he didn’t go to a single lecture. An old term report notes crisply, ‘Ken should spend less time acting: both in and outside tutorials’. Though it is hard to imagine Ken acting (much less acting up), I suspect he would have made a good lawyer or politician. He speaks with great authority and sincerity, and a sense of social injustice infuses his films. However, Loach insists he was never tempted to go into politics. ‘Absolutely not. I don’t think I’d be much good at politics and anyway I prefer film and theatre. It sounds clichéd but film has a unique ability to examine peoples’ deepest feelings. And you can explore that far more in fiction than in politics.’

Despite this, Loach admits, ‘I want to show a different view of the world from the one people normally see’. Indeed, all his films are set against a backdrop of inequality or injustice. Up The Junction, made two years before abortion was legalised, reveals the horror of backstreet abortions; Riff Raff, set in Thatcherite Britain, follows a Northerner in London trying to survive on a builder’s income; Bread and Roses focuses on the exploitation of immigrant cleaners in 1990s Los Angeles.

Certainly, Loach’s work has influenced politics, perhaps more than any other director. His 1966 film, Cathy Come Home, is often heralded as proof that art really can change lives. The film follows Cathy, a young woman whose husband is injured and loses his job: the couple is evicted, their children are taken into care and Cathy ends up alone on the streets. The film was aired on BBC1 and watched by an astonishing 12 million viewers – nearly a quarter of the population at the time. After the showing the BBC switchboard crashed with the number of people calling in to offer help. The film ultimately led to a change in council housing policy and a huge surge of support for the newly founded homeless charity, Shelter.

Such incredible viewing figures for a docudrama would be inconceivable today where only the X-Factor commands such public attention (the final of series 7 claimed over 19 million viewers). Ironically, the proliferation of channels has actually diminished the power of television, as Loach laments: ‘Back then there were only two channels. We hadn’t grown up with television: it was still a relatively new medium and so had a much greater impact. The ever-present mediocrity of most television today has taken the heart out of the medium.’ Sadly ,however, while Loach suggests that cinema has retained a level of influence he cannot name a single film in the last ten years that has had a lasting political effect.

I ask if he has ever changed his mind about the views he promoted in a film and wished, with hindsight, that it had not been released. Surprisingly, he names Cathy Come Home: ‘The end captions suggested that the problem of homelessness could be solved with minor changes of policy. It was only once we’d made the film that it became clear that much more radical changes were necessary. Housing is a very complex issue; we need to look at it in relation to the market economy and employment. Homelessness begs huge questions that we failed to ask in Cathy Come Home.’

As well as his unconventional subjects, Loach’s style of filmmaking is unique: he tries to cast actors who have experience of the subjects he is exploring, and many of his most famous scenes are improvised rather than scripted. Loach describes how, in Land and Freedom, he filmed the scene where Blanca is shot without giving the script to anyone but the actress and her assassin. Thus, when the bullet hits her, the shocked horror of the rest of the cast is genuine. And it shows. Loach gets astonishingly natural performances from even the most inexperienced actors. Yet with such a reputation, he could work with any Hollywood star: why does he so often choose to use unknown actors? ‘You want the audience to believe that the character is real. If you use a known face then the illusion is destroyed. Plus, film acting is not like acting in theatre where you need a sustained performance: that can only come from experience. In a film you don’t need an arc of performance, you just want the individual moments to be true.’

In a world where celebrities often adopt high-profile causes Loach is that rare species, a person who actually lives by his principles. He supports the Palestine Campaign for the Cultural and Academic Boycott of Israel and in 2009 he persuaded the Edinburgh Film Festival to return a grant from the Israeli Embassy. Later that year when the Melbourne International Film Festival refused to return Israeli sponsorship he withdrew his entry, Looking for Eric, from the event. Such setbacks are probably not unusual for Loach and within a year he had released his next film, Route Irish, a thriller set in Liverpool where a young soldier has just returned from Iraq. The film, which explores such characteristic Loach themes as the exploitation of the working-class, the psychological consequences of fighting and government corruption, was selected for the 2010 Cannes Film Festival. Loach’s forthcoming film, The Angel’s Share, looks set to be just as provocative; set in a Scottish distillery, it follows a group of children on community service.

After a fascinating forty-minute interview I still find Loach an enigma. As a person he appears content, as he is entitled to be with such a career behind him and a new film in progress. But he also seems world-weary (if not profoundly disappointed) by the state of filmmaking, politics and society in general.

As we said good-bye I couldn’t help thinking that no matter how successful Loach is, he will never feel his work is complete. With his fierce moral integrity, his preoccupation with the powerless and his own remarkably modesty, he can perhaps best be described as a noble Everyman.