Time was when the term ‘foreign language film’ was synonymous with arthouse cinema. Not any more. Thanks to the commercial success of the likes of Amelie, Crouching Tiger, Hidden Dragon and Amoros Perrros; subtitled films have entered the mainstream. Add to these this new release from Alfonso Cuaron, which, like the aforementioned movies, should pack them in.

The film starts off as no more than a teen sex comedy, albeit one with considerably more sexual frankness than most. Tenoch and Julio are childhood friends doing what boys do at their age: smoking dope and comparing the size of their willies.

All this changes when their girlfriends leave for Europe (“promise not to fuck any Italians”) and they meet Luisa, a beautiful Spaniard married to Tenoch’s effete cousin, Jano. The meeting leads to them taking a road trip to find Heaven’s Mouth beach – a location that only exists in the boys’ imagination.

What ensues is a voyage of discovery that travels way beyond the realms of the usually fey, coming-of-age drama. Although not in any way trying to convey a message, or be judgmental, the camera frequently strays from the protagonists to show a Mexico ridden by class differences and political turmoil, yet at the same time recognising the vibrant beauty of the country and its people.

Complimenting this is an objective voice-over filling in the character’s backgrounds and occasionally their destiny. This device works well and allows the story to gather speed without the need for windy expositions.

Although never losing sight of the fact that this is a comedy, Cuaron provides quite a few jolts along the journey. But it’s a tribute to his assured direction that these never jar, but instead provide an antidote to complacency or sentimentality. As to the frequent displays of naked flesh, this must be one of the few films in which it would have been gratuitous had the characters kept their clothes on.

The cast are first class, particularly Maribel Verdu as Luisa, the older woman who is transformed from a seemingly passive housewife into an uninhibited seductress. The reasons for this metamorphosis are twofold and therefore somewhat ambiguous. The abrupt but perfect ending provides part of the key to this and will have you thinking long after you leave the cinema.

Like its compatriot Amoros Perrros, ‘Mama’ has a very eclectic and wondrous soundtrack. Brian Eno’s By the River provides a particularly poignant moment.

It’s a pity that such a masterpiece has received an 18 certificate, thus preventing the very group who would benefit most from seeing this. When the same thing happened in Mexico, teenagers staged naked demonstrations until the government relented, which they soon did. It’s doubtful if this would happen in the UK, too cold for one thing, but otherwise no effort should be spared to see this wonderfully warm and intelligent film.