Idris Elba spent most of the time filming in one room or another. The room that the film was filmed in, and his hotel room. The schedule was so tight, and the role so intense, that he barely ever had the time or energy to do anything else but prepare and perform.
Producer, Arabella Page Croft said the final edit of the film was only completed 2 days before the premier, which was "close to the wire". They had a final run through of the film on the morning of the premier. She also said she was proud the whole film had been shot in 22 days and all in Scotland.
Writer/Director/Producer Eromose returned to his homeland Nigeria to raise the funding for the film when no funding could be secured in the UK or US. In the end, Thomas raised the entire production and post production budget in Nigeria. Thomas has dual nationality, Nigerian and British.
Eromose edited the film and then Richard Graham was brought on to refine and re cut parts Thomas' edit. Richard Graham's input was invaluable as he somehow managed to shave off 15 minutes of the film but still maintain the integrity of Thomas' edit, which Richard respected. It ended up a good partnership.
Niamh Morrison not only handled prosthetics but also handled aspects of makeup as well. Her work was so authentic that Thomas and other crew found it hard to look at Idris Elba's scars on some days. Particularly the infamous 'back scene' day.