Playwright R.C. Sherriff had seen first-hand the effect of years of war on his friends and knew the fear and terror of waiting for an impending attack, waiting for his journey's end. The characters in the play are a reflection of the men Sherriff had served with in the 9th Battalion of the East Surrey Regiment.
While researching his family history, Sam Claflin discovered that his great-great-grandfather was in a battalion posted to the Battle of St. Quentin--the same battle depicted at the end of the film.
The film's general release (apart from a few earlier screenings at festivals) in 2018 coincides with the centenary of the events shown in the film, which take place toward the end of WW1 in March 1918.
The R.C. Sherriff play on which this was based premiered in London in 1928, with Laurence Olivier in the cast. The 1930 film adaptation, Journey's End (1930), was directed by James Whale.
Journey's End was also made as a film in 1954.