Cartoonist Ronald Searle's delightfully diabolical private-school girls are back in action in The Great St. Trinian's Bank Robbery. Comedian Frankie Howerd plays the head of a train-robbery gang who cleverly hides the loot from their biggest haul (presumably the infamous "Great Train Robbery" of 1963) in a deserted old mansion. The gang waits the traditional seven years for the statute of limitations to run out then returns to the mansion to dig up their $7 million booty. Unfortunately, the joint has been converted into the new site for St. Trinian's School for Girls. Even more unfortunately (for the crooks, but not the audience) those "girls" are all holy terrors. The film's climax occurs during a riotous Parents' Day ceremony, which predictably segues into a wild train chase. Great St. Trinian's Train Robbery might have been funnier had Alastair Sim, the star of the first three "St. Trinian's" entries, made a return appearance.
~ Hal Erickson, All Movie Guide