Those unruly schoolgirl sirens hunt for pirate treasure but end up searching for laughs instead in this very sloppy sequel to the 2007 revamp. Sagging under the weight of too much plot - Rupert Everett's headmistress Miss Fritton discovers she's related to an infamous buccaneer, so the girls go on a hunt for a treasure trove, but a woman-hating secret society wants to upset their plans - this sub-Carry On romp wearily coasts along on the lines of a rudimentary old-school farce rather than anything resembling wit. Everett's parody of Camilla Parker-Bowles feels stale this time around and Colin Firth's embarrassment at having to play the character's ageing love interest has clearly increased. Cast additions include Girls Aloud's Sarah Harding as a rock chick, which is hardly a stretch. Yet she's nowhere near as bad as the depressingly camp villain played by David Tennant, though he does sum up the lacklustre proceedings with the line "Oh, this is interminable".

After a wealthy philanthropist expresses an unusual interest in a ring found by her niece Annabelle, Miss Fritton explains that she's descended from a pirate who, in 1598, stole treasure from another: the philanthropist's ancestor. This discovery sends the racuous girls of St. Trinians on the hunt for buried treasure.