When young Ernesto Guevara set off in 1952 on a Norton 500 motorbike he thought he was going to find the real South America.

Instead, he embarked on journey of self discovery as the iniquities hidden by the Pampas grass and snowfields of the Andes mountains were revealed.

Ernesto (Garcia Bernal) and his travelling companion Alberto Granado (Serna) come from comfortable middle class backgrounds in Buenos Aires and Cordoba.

As we follow their comic road trip astride the misfiring Poderosa (The Mighty One) - collisions, spills and near-misses - it appears the fruition of any teenagers' open road dream.

However, when they leave the comfortable familiarity of Argentina, another way of life, a desperate way of life, is encountered along the road.

They meet Peruvian small-holders kicked off the land and forced to seek work down a mine, Inca descendants decimated by Spanish rule and, most, profoundly, the humble residents of a leper colony.

If this sounds like a worthy political diatribe charting the left-leaning course of two earnest young revolutionaries-in-waiting it's anything but.

Never remotely preachy or patronising, the journey is informed by a rich humour and terrific interplay between the serious-minded Che and the clownish Alberto.

However, the former isn't above some serious flirting with a mechanic's wife which almost ends in disaster while the latter is totally in tune with Che's awakening political conscience.

Garcia Bernal delivers a career-defining performance as the young Che, practically unrecognisable from the Cuban revolutionary he would become but displaying the social awareness that would ignite into full-blooded revolt.

He's superbly supported by the relatively unknown Sernal, who has a hint of the old Colin Welland in a display that both mirrors and balances Garcia Bernal's Che.

Salles demonstrates (again) his sure touch, empathy with character and basic ability to tell a good story well.

Definitely a trip worth taking.

Tim Evans