On 1 April 1963, Ian Chesterton playfully started a snowball fight with Okehurst during morning recess. The fight distracted both teachers from Francis Minto's attack on the snowman built by Gillian Roberts and Susan Foreman, and its vicious response (animated by the Cold), which badly injured Francis. When Gillian and Susan were punished for Francis' injury, Mr Okehurst oversaw the detention.
The detention work detail was to clear ice off the school buildings. Gillian and Susan took blowtorches up ladders to melt the ice, while Okehurst and five boys who were also on detention stayed below. Okehurst and all the boys were killed by the Cold. (PROSE: Time and Relative)
Behind the scenes
Mr Okehurst is a notable example of a character which originated in an expanded universe story (PROSE: Time and Relative) before incorporated in a television episode, in this instance an episode of the spinoff series Class, almost fifteen years after his sole appearance to date.