The Children's Hour by Lillian Hellman

Written by Lillian Hellman, the play is set in a boarding school for girls in the 1930s. Two highly respected women teachers see their reputations torn to shreds when a troublesome and malicious pupil starts an unfounded rumour.
By the time the rumour is proved to be pure invention, both women have suffered irreparable damage, and lifelong friends have failed the test of loyalty.

Revived to great acclaim in the West End in 2011 with Keira Knightley in the lead, it also enjoyed huge success in 1961 in a film version starring Audrey Hepburn & Shirley MacLaine.