die! die! my darling! (1965)

AKA Fanatic.
"One's duty to the Lord must take precedence, must it not?"
Patricia Carroll (Stefanie Powers), arrives in London to marry Alan Glentower (Maurice Kaufmann), but before she does, she wants to pay her respects to Mrs Trefoile (Tallulah Bankhead), the mother of her deceased fiancé. Whilst at Mrs Trefoile's it becomes apparent she blames Patricia for her son's death, and decides Patricia needs to cleanse her soul...
A psychological thriller, rather than a horror. This is mildly diverting, rather than out and out entertainment.

loot (1970)

"I'm a professional. I only marry for money."
Two friends, Dennis (Hywel Bennett) and Hal (Roy Holder) execute a bank robbery, hiding the money in the coffin of Hal's recently deceased mother. Things get complicated when Inspector Truscott (Richard Attenborough) starts to sniff around, as does Nurse Fay (Lee Remick), a gold-digger who gets wind that the boys may have come into money!
Based on the play by Joe Orton and adapted by Galton and Simpson, this is a wonderful, and blackly comic farce, chock full with a number of wonderful characters.