Here are three reasons why biopics fudge facts: to make a romance more romantic, to make characters more universally appealing and to create a more spectacular moment of triumph.

THE RAILWAY MAN (2014)

British soldier Eric Lomax (Colin Firth) was captured by the Japanese in the fall of Singapore and sent to work on the Thai-Burma railroad, where he and other Allied troops and civilians were starved and tortured. To sharpen the narrative of the post-war Lomax as a soul scarred by torture, who finds relief in the arms of the free-spirited Patti (Nicole Kidman), the movie omits the fact that Lomax was already married and a father of two when he met Patti.

THE IMPOSSIBLE (2012)

The story of British couple Henry (Ewan McGregor) and Maria (Naomi Watts, left, with Tom Holland) and their children who are caught in the 2004 Indian Ocean tsunami, while on holiday in Thailand, is based on the real experiences of a Spanish family. But the film's producers thought that an English-speaking family played by Hollywood stars would sell better to global audiences.

HIDDEN FIGURES (2017)

In the early days of the American space programme, the National Aeronautics and Space Administration (Nasa) recruited black women in the South to work as "computers", or human calculators. These women would contribute to the most important rocket launches in Nasa's history.

In one of the movie's dramatic moments, white department head Al (Kevin Costner, left, at a red-carpet event) is infuriated by his workplace's segregated facilities and takes an axe to a "coloureds" sign above a women's toilet. In real life, no such intervention by a white boss ever happened.

The film also stars (from far left) Janelle Monae, Taraji P. Henson and Octavia Spencer.