Cosh Boy (released in the United States as The Slasher) is a 1953 British film noir directed by Lewis Gilbert and starring James Kenney and Joan Collins. It was made at Riverside Studios in Hammersmith. Plot Based on an original play by Bruce Walker, the film tells of the exploits of 16-year-old delinquent youth Roy Walsh (James Kenney) and his gang in post-World War II London. The gang starts off by mugging women. Later, Roy becomes infatuated with Rene (Joan Collins), the sister of one of the gang members; but, already having a boyfriend, Brian, she rejects Roy, to his fury. Later the gang beats up Brian. Roy menaces Rene, who eventually submits to him. When she informs him that he has made her pregnant and urges him to marry her, he decides he wants nothing more to do with her. Roy's mother, Elsie Walsh (Betty Ann Davies), is involved with Canadian Bob Stevens (Robert Ayres), who urges her to marry him so he can take Roy "in hand" before it's too late. Roy hates Bob. Bob works as an assistant manager at the Palidrome dance hall, which becomes a target for the gang. Another member of staff appears on the scene whom Roy shoots and wounds (he initially believes he has killed the man). Later that night a crowd of women arrive on the doorstep with Rene's mother, who adds that the police are on their way. Bob arrives, removes Rene's mother from the scene and decides to give Roy a thrashing - for his own good - before the police arrive in the belief that, if the judge hears he has already received a thrashing, his sentence might be lighter, which will be easier for his mother to stomach. The police arrive just as Bob is brandishing his belt in readiness. Bob lets them in, and in reply to their enquiry as to his identity he says he is the boy's stepfather, as "his mother and I were married this morning". The senior officer congratulates him. Then, seeing the belt in Bob’s hand, he smiles, and suggests to his colleague that they go and arrest the other gang member first and come back for Roy later. Bob begins thrashing Roy as the scene cuts to outside and the mob of women listening to Roy's cries and shrieks for help. The detectives then walk away silently, into the night.