Lessons

Charlie Barlow is having himself a ball. He is lecturing a room full of officers on the proper way to investigate a murder, laying out the procedure step by step the way only he can, and he is enjoying himself far too much for a man about to be interrupted. The room is full of trainees with notebooks, and Barlow is in his glory. Then the lecture is overtaken by reality. The body of a teenage girl has been found washed up on the beach, and Barlow's classroom exercise has become the real thing, in front of an audience.

The officers who were taking notes are now part of a live investigation, and Barlow has to solve the case while teaching it. The prime suspect turns out to be a window cleaner. The father of one of the people involved is grieving and difficult, and nothing in the textbook quite covers that. The beach gives the case an open, exposed quality, and the sea keeps whatever evidence it has decided to keep. The lecture promised tidy answers. The beach has other ideas. The episode's quiet question is whether the lesson survives contact with the crime.

Elwyn Jones and Arnold Yarrow wrote it, and Leonard Lewis directed. Stratford Johns is Barlow, Frank Windsor is Watt and Norman Bowler is Hawkins. David Allister is Jackson, David Lloyd Meredith is Evans and Susan Tebbs is Donald. John Ringham plays Chief Insp. Jack Fox, Crispin Gillbard is Police Cadet Wellbeloved, Michael Gaunt is Det. Con. Timms and Glynn Edwards is Mr Vernon.

There is a satisfying cruelty in the structure. Barlow loves to be the one who knows, and the episode keeps handing him things he cannot predict. The window cleaner. The grieving father. Neither behaves like a textbook, and the cadets get a better lesson than the one on the board. But the episode's real subject is the gap between what Barlow teaches and what the job demands, and it keeps widening.