By applying cutting-edge restoration techniques to footage shot at the time, Jackson has crafted an historical portrait of matchless immediacy and power, in which young souls lost in a century-old war stare out across the years and meet our gaze.

Jackson and his entire production team have produced a film which is both a form of cultural monument and a monumental cinematic achievement.

It's a simple thing but if it's not the first film to show World War I taking place under heavenly blue skies it certainly feels like it is. The odd clarity is a horrible but absolutely necessary gift from Jackson and Walsh to these men.

Using nothing but the voices and the images from the past, They Shall Not Grow Old is a powerful tribute to every veteran and one of the most empathetic portraits of war ever created. His grandfather would be proud.

This was, undeniably, a risky proposition; no one wants to airbrush history. But by thoughtfully employing cutting-edge technology, Jackson has instead created an essential portal connecting audiences of the present to his subjects in the past.