BY JULIE McCAFFREY

It’s the murder mystery that has gripped the nation and outraged diehard Agatha Christie fans. The BBC’s Ordeal by Innocence has all the glamour, intrigue and snobbishness of a Christie – but bad language, fruity storylines and a – gasp! – rewritten plot has given it a modern edge.

Set in a country manor in 1954, the Argyll family is torn apart when matriarch Rachel is bludgeoned to death around 9pm on Christmas Eve and one of her five adopted children is accused.

When his cast-iron alibi turns up 18 months after the accused son has died in jail, it’s clear one of the family has blood on their hands. But who?

With no spoilers from the final episode this Sunday, we examine the off-screen secrets and scandals of the drama that has enthralled millions of viewers.