What is the story behind Stokes' folded middle finger gesture after victory?

All-rounder Ben Stokes' folded middle finger gesture after England's Cape Town Test victory against South Africa was a tribute to his father, Ged. Ged got part of his finger amputated instead of getting it operated to continue his rugby league career in 1980s as he couldn't afford to miss matches. Ged is currently hospitalised in Johannesburg following a sudden illness.