The film was co-commissioned by 14–18 NOW and Imperial War Museums in association with the BBC, who approached Jackson in 2015 for the project.[6] According to Jackson, to make the film, the crew of They Shall Not Grow Old reviewed 600 hours of interviews from the BBC and the IWM and 100 hours of original film footage from the IWM.[7][8] The interviews came from 200 veterans, with the audio from 120 of them being used in the film.[9] After receiving the footage, Jackson decided that the film would not feature traditional narration and that it would instead only feature audio excerpts of the soldiers talking about their war memories, in order to make the film about the soldiers themselves. For the same reason, it barely features any dates or named locations.[8]
"This is not a story of the First World War, it is not a historical story, it may not even be entirely accurate but it's the memories of the men who fought – they're just giving their impressions of what it was like to be a soldier."
—Peter Jackson at the film's premiere.[7]
Jackson stated: "We made a decision not to identify the soldiers as the film happened. There were so many of them that names would be popping up on the screen every time a voice appeared. In a way it became an anonymous and agnostic film. We also edited out any references to dates and places, because I didn’t want the movie to be about this day here or that day there. There's hundreds of books about all that stuff. I wanted the film to be a human experience and be agnostic in that way. ... I didn't want individual stories about individuals. I wanted it to be what it ended up being: 120 men telling a single story. Which is: what was it like to be a British soldier on the western front?"[8]
In another interview, he stated "[The men] saw a war in colour, they certainly didn't see it in black and white. I wanted to reach through the fog of time and pull these men into the modern world, so they can regain their humanity once more – rather than be seen only as Charlie Chaplin-type figures in the vintage archive film."[10]
Jackson's own paternal grandfather, Sgt. William Jackson, to whom the film is dedicated, was British and fought in the First World War.[11] Peter grew up with his father telling him his grandfather's war stories.[12] Jackson stated that after making the film, he now had "a greater understanding of what my grandfather would have gone through".[10]
Jackson did not receive any fee for the making of the film.[6] Although only a small part of it was used, Jackson's crew visually restored all 100 hours of footage the Imperial War Museums sent them for free, "just to get their archive in better shape".[8]
It was produced by WingNut Films with House Productions as executive producers, and was supported through 14-18 NOW by the UK's National Lottery through the Heritage Lottery Fund, Arts Council England, the Department for Digital, Culture, Media and Sport with other public and private funding including corporate supporters.[13][14][15]
