Swedish slowcoach Roy Andersson took seven years to complete A Pigeon Sat on a Branch Reflecting on Existence, the third part of his “existence” trilogy. But that’s nothing compared to the glacial progress of Portuguese auteur Vítor Gonçalves – whose second feature film, The Invisible Life, is about to be released in the UK 29 years after his first, Uma Rapariga no Verão (A Girl in Summer). Gonçalves, now 64, rivals Andersson in his commitment to uncompromising, old-school art cinema, and his extended gap between features – interrupted only by a TV movie, Meia Noite (Midnight) in 1988 – must be some kind of record.

Rather like Andersson, Gonçalves turns out to be a genial, self-deprecating presence: soft-voiced, and prone to occasionally losing himself in his own train of thought. He has not been idle in this three-decade hiatus: most of his time has been taken up lecturing on the film-directing course at the Lisbon theatre and film school (Escola Superior de Teatro e Cinema), as well as taking it upon himself to shepherd feature films by former students such as Pedro Costa (O Sangue), Ana Luísa Guimarães (Nuvem) and Joaquim Sapinho (Bosnia Diaries) – no doubt at the expense of his own directorial career. However, Gonçalves says, “the school defies you to be alert. There has not been one single day I have not been immersed in cinema.”

Gonçalves has inched back into production with the help of Skye-based producer Chris Young; the two became friends in the late 80s after Young saw, and was deeply impressed by, A Girl in Summer. Plans to make a film together back then were put on hold in the mid-90s as other commitments took over, but Young never lost faith: buoyed by an unexpected windfall from his participation in The Inbetweeners TV series and record-breaking film spin-off, another attempt was mounted a decade and a half later. The Invisible Life was filmed in Lisbon in 2009 and 2010, with local producers Rosa Filmes on board, but it wasn’t completed until summer 2013 – partly due to an extensive search for a soundtrack composer, according to Young, and Gonçalves’s painstaking work on the sound mix.

Slow but steady ... Vitor Gonçalves.

So what has Gonçalves come up with, after this epic wait? It would hardly surprise anyone to discover that The Invisible Life is a melancholy fable about a middle-aged man reluctant to confront the future, immersed in his own fears and unrealised ambitions. It moves backwards and forwards in time, confronts the permanence of death and the persistence of ideas, mourns for lost love and ends on an oblique sense of hope. But Gonçalves doesn’t talk about his film in terms of autobiography – even though his principal character, Hugo, is confounded by the death of an older colleague and mentor, Antonio; even as Gonçalves himself was mentored years ago by film-maker António Reis, into whose shoes he stepped at the Lisbon film school, on Reis’s death in 1991.

“People have asked me a lot about Antonio, but it is really a coincidence. In António Reis I had a great master – he was an extraordinary man, and an extraordinary director, but when I shot the film I was not thinking about him at all. Of course, I was conscious of the fact that, in the film, Antonio is a father figure, and for Hugo it is a way to avoid facing his solitude. He prefers to live with the dead than the living; he feels more secure this way. If there is a conclusion to the film, it is Hugo’s ability to say goodbye to people who have died, to say farewell without the fear of forgetting them.”

Sombre stuff, but Gonçalves is one of the last of a breed that is heading for extinction: the arthouse director anxious to talk in terms of ideas and structure, rather than anecdote or irony. Gonçalves repeats that his film “is about someone who finds it difficult to dream about his future”, and in many ways picks up thematically from A Girl in Summer. The protagonist in the earlier film is younger, and female, but is similarly preoccupied by intimations of the life she would like to lead, and the aimless, unsatisfying reality.

A Girl in Summer

When A Girl in Summer first appeared, it seemed to herald a new, Portuguese front in European art cinema – along with film-makers such as Manoel de Oliveira, Paulo Rocha, and Reis himself, along with his co-director wife Margarida Cordeiro. It didn’t quite work out like that – for Gonçalves at least – and in retrospect A Girl in Summer looks a little like a relic from another era, when art cinema was a vehicle for rarified ideas and complex socio-political musings, rather than a showcase for coffee-table landscapes or gruesome sexual violence.

Certainly Gonçalves would appear to be preoccupied with some very big ideas: “The last thing I wanted,” he says, “was to be superficial. It would destroy the film.” He says he thought constantly “how to portray with a sense of truth the inner journey of life” and focused on the “moment in life when we have a sense of our own mortality”. He explains that the short 8mm sequences shot by Chris Young’s artist wife Julie Brook, that he incorporated into The Invisible Life, are “some sort of waking dream” for his central character, which “allow him to be in contact with himself in a less cautious way”. He gets particularly excited when he starts talking about his interest, “obsession” even, with the “meta-reality” of space; he doesn’t mean the cosmos, of course, but space in the sense of simple, enclosed area. He says that he spent much of his time on The Invisible Life filming interesting-looking angles and corners that weren’t accounted for the script, much of which ended up in the final cut. It’s as if, he says, there was an invisible film alongside the official one – the Invisible Life’s invisible life, as it were.

Sense of truth ... The Invisible Life

All this shouldn’t completely obscure some of the more eye-catching aspects of Gonçalves’ backstory. Apart from the fact that a sliver of The Inbetweeners’ money is responsible for resuscitating his career, it turns out he is the son of a radical leftist army officer who briefly served as Portugal’s prime minister in the early 1970s, after the carnation revolution that displaced the authoritarian Estado Novo regime headed, for most of its existence, by António Salazar. History’s verdict is certainly divided on Vasco Gonçalves, portrayed in many quarters as a dangerous communist, but it’s interesting nonetheless to hear his son talk about him in family terms. Gonçalves says his father, who died in 2005, expected him to follow him into engineering, but he opted for film school. Gonçalves says, at the time, he was just looking to “make a break” from his family and his father’s political life, but now suspects that Vasco’s own love of film subconsciously influenced him. The Invisible Life’s preoccupation with father figures now starts to look entirely logical.

With The Invisible Life out of his system, Gonçalves is now roaring ahead; he’s working on a third feature already. Though, he says, now he wants “to go to a different place”. “With Invisible Life, I just talked about the dark. This time I would like to talk about the vividness of life.”

• The Invisible Life out now. The Girl in Summer will be released on DVD in September.