Pour the icing sugar in a large bowl. Place a pan over a high heat until very hot. Add the popcorn to the pan and put on the lid. Shake the pan around for 30 seconds or so. Switch off the heat.
The heat of the pan should finish off the popcorn. When the popping has subsided, remove the lid. Add the popcorn to the bowl and stir well.
To colour the popcorn, push the raspberries through a tea strainer or sieve, and collect the juice. Put a teaspoon of this into a bowl, add half of the popcorn and stir to colour all over.
Cut a length of thread to fit around your child's neck. Using a large, sterilised darning needle, thread the coloured and plain popcorn on alternately. Also intersperse with dried fruit, if desired.