Professor Popper's Problem is a 1975 British children's science fiction comedy film directed by Gerry O'Hara, starring Charlie Drake in the title role. Featuring a number of child actors, Todd Carty, Milo O'Shea, and Sydney Bromley also appear. The serial picture was produced for the Children's Film Foundation (CFF) by Roy Simpson of Mersey Film Productions, presenting a screenplay by Leo Maguire and soundtrack by Kenneth V. Jones. The story concerns an eccentric science teacher named Professor P. Popper, miniaturised with a group of pupils after accidentally consuming shrinking pills. A student apart from the group volunteers her help, as, separately, does a colleague of Popper's. As they search for an antidote, Popper and his entourage must see off multiple dangers, including criminals determined to steal his shrinking formula.