Mason Jr (Ellar Coltrane) in Boyhood.Universal Pictures

Indie director Richard Linklater is known for his eclectic output, from making Jack Black musical comedy School of Rock, to adapting Philip K. Dick's A Scanner Darkly into a rotoscoped narcotic nightmare. But during the years those movies and others were being planned, produced and released, what has been quietly simmering away on the backburner is the film for which the director will be most remembered, his magnum opus: Boyhood.

Described by the director as, "One story made up of a lot of little pieces," it's a picture of truly colossal ambition. Shooting with the cast for a few days every year over a period of twelve years, the film follows the family life of Texan boy Mason Jr (Ellar Coltrane) in his adolescent journey through the ages of six to 18.

From when we first see the cherub-faced youngster looking up at the sky to him taking in the sensational sunset at Big Bend national park during his first day at University, in less than three hours we see Mason evolve from child to adult, an organic transformation that unfolds right before our very eyes. Shooting over a length of time that allows us to see a progression of character, both physical and emotional, that is these days reserved only for high-end US television, Boyhood is the ultimate coming-of-age drama.

Its behemothic technical achievement is equalled by the sublime turns of the actors involved. To think they had to dip in and out of their roles every year for over a decade and yet the final product flows from start to finish so harmoniously is astounding.

In just 164 minutes you see Mason Jr (Ellar Coltrane) grow up right before your very eyes.Universal Pictures

In the case of the film's protagonist played by Ellar Coltrane, it is also simply good fortune. He might worrying begin to resemble Hayden Christensen at one point, but that's as far as the similarities go, as Coltrane manages to carry the film along with his detached demeanour but piercing turquoise eyes.

As his divorced father Ethan Hawke plays the familiar likable loser, a free-spirited rebel who chastens at but ultimately takes on responsibility, similar to his Jesse character in Linklater's Before trilogy of films. But the beating emotional heart, and selfless hero of the piece, is Patricia Arquette as his mother.

Despite being saddled with husbands who are either absent, alcoholic or abusive (sometimes all three), it is the fact she soldiers on, finding the strength to study hard for her job and make sure her kids get the best she can provide, only for them to eventually fly the nest and leave her alone, that makes her one of the most heroic depictions of motherhood ever seen on screen.

Throughout we see Mason's perspective of the world, where the Houston suburbs he grows up in are both insular and vast, and the adults around him are flawed and frustrated, even as they try and impart wisdom on to their offspring.

Mason Jr (Ellar Coltrane) and his father (Ethan Hawke) in the film.Universal Pictures

Lessons play a crucial part in almost every exchange between child and adult in Boyhood, such as when their red-faced father provides a frank sex education lesson to his two teenage children, or later when Mason's photography teacher lectures him to work hard in the dark room. To ram this point home Mason's mother even goes from being taught psychology at the local college to later teaching it. These adults come across not so much desperate to assert authority as trying to make sure their children don't make the same mistakes, despite being, as Mason observes, "as f**king confused as I am".

The rites of passage we see Mason go through; the change of house, of school, the first beer, girlfriend and job; form a series of snapshots in the film, a collage of one person's life. Seen on screen over 164 minutes this appears a life in fast-forward, inexorably charging ahead with melancholic momentum.

But in Linklater's deft hands the movie manages to bustle along with joyful energy, the changing years serving to propel the narrative of what would otherwise be a disparate collection of moments. What makes Boyhood's format work so well on screen is that both cinema and our memories provide an edited experience, where we learn to accept that whilst we might all be enslaved to the passage of time, you can treasure the moments of wonder and happiness that form part of it.

As Mason is at one point told, "People always say seize the moment, but it's the other way round, the moment seizes us".

Boyhood will be released in UK cinemas nationwide on 11 July.