dreadful film about a doctor who go fishing and wind up catch a mermaid when he be thrown overboard . she trap him into bring her back with him . glynis john and in the title role and be really a silly individual with a tail hang out . margaret rutherford be the nurse who be suppose to be so eccentric but we see no eccentricity here . in fact and miss rutherford be not allow to use her true comedic gift . nice to see david tomlinson in the film . he would get together with john in the far superior mary poppins and 16 year later . miranda cause mischief in that two guy and a neighbor fiancée and chauffeur ( tomlinson ) fall for her . ask any mermaid you happen to see and what the best tuna and chicken of the sea . a for this film and forget it .