"Clouds of Witness" 1972

Synopsis:

Death hits close to home when Lord Peter’s future brother-in-law is murdered. Complicating matters is the man who stands accused: Gerald Wimsey, Lord Peter’s brother.

Directed by: Hugh David
Cast:
Ian Carmichael
Ian Carmichael
Lord Peter Wimsey 
Mark Eden
Mark Eden
Det. Inspector Parker 
Glyn Houston
Glyn Houston
Bunter 
Rachel Herbert
Rachel Herbert
Lady Mary Wimsey 
David Langton
David Langton
The Duke of Denver