Ken Loach is a lot of things, but retiring clearly isn't one of them. At the age of 77, he looks leaner and livelier than some film-makers half his age, and when I meet him one early morning in Soho he appears to be less in need of a strong shot of caffeine than I do. Engaging, entertaining, and ready to talk, he's eager to get to grips with my lengthy list of questions from Observer readers ("yes, yes, that sounds really interesting, let's see what you've got, let's go") and to discuss films, politics, and football with equal vigour. But first things first - what about those stories (since debunked) of Loach's imminent retirement? Back in August of last year, Loach's longtime producer, Rebecca O'Brien, was quoted as saying that Jimmy's Hall, a vibrant account of James Gralton's real-life battles with church and state in 1930s Ireland, would be "probably the last narrative feature for Ken". Yet as Loach heads off to compete in Cannes for a record 12th time (he laughs at the suggestion that he is now "part of the festival's furniture"), it's clear that he's still going as strong as ever. So what happened?
"It was at the moment of maximum pressure, just before we started to shoot," he explains, somewhat bashfully. "And I just said 'I can't do this any more'. I was away quite a long time on this one, and it was a large undertaking - a period film with a big cast. I was reaching the point where I just wasn't sure that I could carry it off any more. But that was at the start of production. Of course, by the time you get to the end you feel rather less daunted by it. So maybe I won't retire; maybe I'll do a documentary, or something more documentary-like. The problem is that there are just so many things you want to get involved with. Although my missus wouldn't be too pleased to hear that."
While confirming that a "smaller scale, contemporary drama" is not out of the question, Loach insists that "I wouldn't do something on the scale of Jimmy's Hall again; nothing that required that much constructive energy. The thing is, with a dramatic project like this, somebody's got to run around and make it happen. It's an early start - the alarm goes off at six, or half five - and I'm slow in the mornings anyway. Then you finish late. You have to psych yourself up every morning of production, and over a period of weeks and months beforehand."
Documentaries, on the other hand, seem to offer the perfect opportunity for a director full of creative fire but wishing to scale things back. "With documentary, you observe something that you haven't set up," says Loach enthusiastically. "Jimmy's Hall is set in Ireland in the 30s and everything that went under the camera we had to generate. With documentaries you don't have to do that. And archive documentaries are the best of all because the film just arrives in the cutting room! And you do the odd interview or two, which is always nice. So archive documentary is basically the genre of choice for the senior director."
It was the screenwriter Paul Laverty who first got Loach interested in the subject of Jimmy's Hall. Having emigrated to America in 1909, communist activist and local legend James Gralton returned to Ireland where he provoked the ire of the authorities by opening a community hall offering teaching, music, radical thought, and (most alarmingly) dance. Accused of spreading immorality and sedition, Gralton became the focus of attacks from Catholic clergy and local officials alike, all of whom tried to run him out of town. "It just brought so many things together," says Loach. "The idea of a free space, resistance, progressive ideas, revolutionary ideas, music, dance, fun, enjoyment - and an oppressive society that wants to squeeze the life out of it."
Loach's enthusiasm for the material shines through every frame of Jimmy's Hall, which is alternately uplifting, provocative, educational, touching and tender. It's also, despite its historical setting, surprisingly contemporary, with descriptions of the economic depressions of yesteryear sounding as if they were ripped from the pages of today's papers. "Yes, the situations are exactly comparable," Loach agrees, "as is the deriding of any serious opposition, the absence of a real left alternative."
Having made his big-screen feature film debut with Poor Cow back in 1967 and won the Cannes Palme d'Or for The Wind That Shakes the Barley in 2006, Loach attributes the longevity of his extraordinary career to "fantastic producers like Rebecca O'Brien, and writers like Paul Laverty. The writers are still the most undervalued element in this whole process. It's so obvious, but you can only direct what is there in the script. And people forget that. Of course in television it's the other way around.
"When I started out with [the BBC's] The Wednesday Play, the play was 'by' the writer. That came from the theatre, and the director's job was to elucidate and express the writer's ideas. Well, the process is the same in film, but for some reason in film the director rather than the writer gets all the credit. Or the blame! It's bizarre. But if it works it has to be a collaboration. There's a heresy which is perpetuated by film school that to be a great director you have to write your own stuff. It seems to me the big weakness in most films is the writing. You can learn directing, but you can't learn writing."
OK Ken, so enough of the small-talk; are you ready to face the Observer Q&A?
"Yes, yes, I'm ready."
What comes first: the quest for truth or the desire to make a piece of cinema? Does cinema - your cinema - have to tell the truth? Do you manipulate the truth to tell the best story?
Samantha Morton, actor/director
Ken Loach: Well, the best story is the true one, isn't it? I'm sure Samantha, who is terrific, would say the same. The point is to make good cinema in order to show that truth; to elucidate it, to tease it out. Moment by moment responses can be true or fake. And then there's the importance of the story itself; why tell one story rather than another? There are a thousand stories you can tell - why pick that one? It's got to have a significance beyond its own narrative. So there's a kind of general reflection beyond the surface events of the story.