Ellen E Jones and Mark Kermode investigate whodunnits and murder mysteries on screen, ahead of the streaming release of new Knives Out mystery Glass Onion.

Mark talks to Glass Onion director Rian Johnson about why whodunnits are so enduring, who left him star-struck on set, and the classic films and books that inspired his new mystery.

And Ellen takes a deep dive into the camp 1973 cult whodunnit The Last of Sheila, written by actor Anthony Perkins and composer Stephen Sondheim following their own outlandish murder mystery parties. Ellen talks to writer Kyle Turner about Sondheim’s love of mysteries and the real life stories behind the film. She also speaks to the legendary Dyan Cannon about the larger-than-life Hollywood agent Sue Mengers who inspired her role in The Last of Sheila, and about the film's legacy as a cult classic.

This week's Viewing Note is courtesy of actor and director Richard Benjamin.

Producer: Jane Long