[4] The film follows two sisters who are brought up in a tightly knit group of Jehovah's Witnesses in Oldham and the tension that results from one of them being disfellowshipped.

Oldham-based Jehovah's Witness Ivanna Whitling lives with her two adult daughters, Alex and Luisa, who are also members of the congregation.

She briefly talks to her mother in the cloak room after the funeral; they hug and Luisa cries loudly in grief.

When Luisa goes into the kitchen to get her mother a glass of water, Ivanna grabs Leanne out of her bassinet and takes her out to the car.

The film was written and directed by Daniel Kokotajlo, who had been raised as a member of the Jehovah's Witnesses but left in his early twenties.

[6] Time Out reviewer Joseph Walsh praised the performances of Finneran, Parkinson, and Wright, while describing the film as "a standout British drama that pointedly asks us to question the strictures of institutionalised religion.

"[7] Writing for The Sunday Times, Edward Porter called Apostasy "a moving depiction of a family constrained by the rules of life as Jehovah's Witnesses".

[8] The New Statesman reviewer Ryan Gilbey noted the film's "intensely controlled and concentrated ... sensitivity towards an austere religious community easily demonised.

"[9] The film received over 21 nominations worldwide, including six BIFA nominations for Most Promising Newcomer (Molly Wright), Best Supporting Actress (Molly Wright), Best Debut Screenwriter (Daniel Kokotajlo), Best Casting (Michelle Smith) and Best Debut Producer (Marcie MacLellan).