Juice the lemons into a sieve over a small saucepan.
Add the Whitworths caster sugar and heat gently until the sugar has dissolved.
Set aside to cool, pour 200ml of cold water into a measuring jug and add the lemon mixture.
Blend the raspberries with the icing sugar, push the puree through a sieve and stir into the lemonade.
Pour into the ice lolly moulds until they are almost full. Place the lolly sticks/lids on the moulds and return to the freezer for 5-6 hours or ideally overnight.
To release the lollies from their moulds simply dip into a cup of boiling (or hot) water for 5 seconds, remember to be careful!
Enjoy your refreshing lollies!