If

if.... is a 1968 film written by David Sherwin, directed by Lindsay Anderson, and starring Malcolm McDowell, in his film debut, as Mick Travis.

The film is set at a Boarding School, and is best known for the climactic sequence in which conflicts between the students and the school authorities escalate into outright warfare with automatic weapons.

Sherwin, Anderson, and McDowell collaborated on two further films, O Lucky Man! and Britannia Hospital; both also feature McDowell as a character named Mick Travis, but they do not constitute a series except in Broad Strokes.

This film provides examples of:

 * Boarding School of Horrors
 * Deliberately Monochrome: Some sequences are in black and white. Accounts vary as to how much this was for artistic reasons and how much was down to technical difficulties and budget restrictions.