<P> The Sultan of Makyad (Eric Pohlmann) wants to send his daughter Fatima to a school in England, and asks her governess Miss Anderson to recommend one: she recommends St Trinian's in the county of Barchester . This suits the sultan perfectly: as his racehorses are trained there, he will be able to visit Fatima and his horses at the same time . </P> <P> At St Trinian's, Miss Holland the accountant, explains to headmistress Millicent Fritton (Alastair Sim) that they need cash, not cheques . Then Fritton's twin brother, bookmaker Clarence (Alastair Sim), arrives with his previously expelled sixth form daughter Arabella (Vivienne Martin). He gets his sister to re-enroll her so she can befriend Fatima and get information on Arab Boy, the Sultan's horse that will run in the upcoming Cheltenham Gold Cup against Blue Prince, the horse he and his associates have backed . Assistant headmistress / physics mistress Buckland (Mary Merrall) enters the office to introduce Fatima and two other new girls to Fritton, and Fatima meets Arabella . Fritton explains St Trinian's to the new girls: "At most schools, girls are sent out quite unprepared for a merciless world but, when our girls leave here, it is the merciless world which has to be prepared ." Fritton takes the new girls to meet the staff: Miss Brimmer (Renée Houston) arts and handicrafts mistress; Miss Wilson (Beryl Reid) maths mistress; Mlle . de St Emilion (Balbina Gutierrez) French mistress; Miss Drownder (Hermione Baddeley) geography mistress; Miss Gale (Irene Handl) English literature mistress; Miss Waters (Betty Ann Davies) the scripture and needlework mistress; and Miss Dawn (Joan Sims). </P> <P> Barchester Police Superintendent Kemp Bird (Lloyd Lamble), in the hope of getting help to stop the crime wave that has occurred in his area since the new term started at St Trinian's, goes to London and meets with Ministry of Education official Manton Bassett (Richard Wattis). Bassett refuses to help: the two inspectors he has sent there have both disappeared . Kemp Bird arranges to send his girlfriend, Sgt . Ruby Gates (Joyce Grenfell), to St Trinian's, undercover, as games mistress Chloe Crawley . </P> <P> When Crawley arrives, Fritton takes her around the school: she finds the fourth form girls using the science lab to make gin, which Flash Harry (George Cole) sells for them; and the sixth form girls learning about French wine regions from the geography mistress . Florrie (Jill Braidwood), the school snoop, hears Arabella tell her father about a trial run the next day and after teasing the fourth form girls about what she has heard, is forced to tell them about the trial . The next morning Arab Boy goes through the trial run timed by the trainer, by Arabella with some other sixth form girls, and by a hidden group of fourth form girls . Now both the sixth and fourth form girls need to find out the weight of that day's jockey, stable boy Albert Faning (Michael Ripper): the sixth form girls have Amanda (Belinda Lee) seduce him to get his weight, while the fourth form girls calculate it . The result is that Arab Boy is sure to win the race . The fourth form girls ask Harry to place a bet for them on Arab Boy but, he tells them, they won't make much with the little more than £ 3 they have, even at the 10 - 1 odds . So, the girls ask Fatima if they can borrow her pocket money for the bet . Fritton is told by the bookkeeper that they have £ 400 in the bank and are £ 4000 in debt . When Fatima, accompanied by four girls, asks for the £ 100 that Fritton is holding for her, the girls explain that they want to place a bet on Arab Boy, who is a sure winner at 10 - 1 odds; Fritton doesn't give Fatima the money, but does get an idea . She summons Harry, who tells her that he places bets for the girls, and asks him to bet the school's remaining £ 400 on Arab Boy in order to win the £ 4000 needed to cover the school's debt . Arabella tells her father the disastrous news of Arab Boy's strength and suggests they "nobble" the horse, but Clarence rejects that idea . Arabella suggests he give it some thought and, should he change his mind, come to St Trinian's the next day, ostensibly for the field hockey match . Crawley and some of the sixth form girls are setting up the net for the match, when the girls run off . Crawley chases them and finds them, with two men and Miss Drownder, having a "French lunch", as she later reports to Fritton . Fritton explains that she need not worry: the men are former ministry inspectors Eric Rowbottom - Smith (Guy Middleton), now the school's gardener, and Wilfred Woodley (Arthur Howard), the new fencing master . Before the match starts Arabella, with some of the field hockey team members, meets with Clarence and his partner Benny (Sidney James). They opt for Arabella's plan to "borrow" the horse until the race is over, which is overheard by Florrie, who is tortured by the fourth form girls for this information . When Crawley goes back to the match, Harry goes to Fritton with a letter he has stolen, which proves that Crawley is really Sgt . Gates . The next morning, with the stable boy's collusion, the horse theft is carried out--almost; in fact, the fourth form girls have taken him . Clarence and Benny are told by their henchman that when they went to get the horse, it was not at the stable . Fritton sees Maudie (Marigold Russell) riding Arab Boy up the stairs, and goes to the fourth form dorm to investigate . She finds the girls, Harry, and Arab Boy and insists they get the horse out of the school before dawn, when Fatima will pretend to find and return him . She gets the girls to promise to carry out this plan . </P>

Where was the belles of st trinians filmed