Fictional British boarding schools - Telegraph Cartoonist Ronald Searle dreamt up the unruly girls school of St Trinian's in the 1940s, filling five books with the outrageous antics of his stockinged anti-heroines. The 1950s St Trinian's films, featuring a memorable Alastair Sim in drag as the headmistress, remain popular to this day. Picture: Moviestore Collection/Rex Features