According to Terence Stamp, the film was mostly improvised and first takes were always used. Two cameras filmed simultaneously to capture the spontaneity of the performances.
In Steven Soderbergh's thriller The Limey (1999), flashbacks involving the main character played by Terence Stamp are scenes from 'Poor Cow'.
Director Ken Loach briefed his actors separately, often with conflicting information. For example, in the improvised scene where Joy throws stew over Dave, Terence Stamp was not expecting it, so Carol White's reaction was genuine.