The Bill - Season 11 Episode 18 A Fighting Chance
Overview: Marshall and Stamp attend the scene of a violent assault, and Marshall gives chase to a suspect. However, when he confronts her, she is forced to use her baton, and during the struggle, breaks the arm of the suspect. However, when the victim gives her initial first statement, Marshall discovers he may be an innocent man, until he strikes again and the witness reveals the real truth behind the first incident.