1.Heat oil in large heavy-based saucepan; cook corn over high heat, covered with a tight-fitting lid, shaking pan occasionally, until popping stops. Transfer to large bowl.
2.Combine sugar, the water and colouring in medium heavy-based frying pan; stir over heat, without boiling, until sugar dissolves. Bring to the boil; boil, uncovered, about 15 minutes or until a teaspoon of mixture “cracks” when dropped into a glass of cold water.
3.Remove pan from heat. When bubbles subside, add popcorn; stir to coat with toffee mixture.
4.When popcorn mixture has candied, spread onto foil-lined oven tray to cool.
Use food colouring of your choice. Popcorn can be made two days ahead; store in an airtight container at room temperature.Note