Griffiths Jones is ("Dr. Paul Martin") who leaves his wife to go on a Cornish fishing trip where he falls foul of mischievous mermaid "Miranda" (Glynis Johns) who holds him captive in her underwater grotto. Her condition for release is that he take her to London where, abetted by Margaret Rutherford as "Nurse Carey" she wreaks havoc, flirting with all the men she meets. It's a rather one-joke film that starts engagingly enough, but as the joke grows thin - and, frankly, preposterous, the performance of Johns starts to grate a little. Googie Withers is quite good as the doctor's somewhat sceptic... read the rest.