Blitz the watermelon flesh in a food processor for a few seconds, until slushy.
Press the blitzed melon through a sieve into a large jug or bowl to extract all the liquid, and get rid of any lumps or pips.
Stir in the lime juice, and then the honey to sweeten (add more or less to taste).
Transfer to a pitcher and place in the fridge to chill for at least 30 minutes.
Add ice cubes, stir, then pour into tumblers. Serve garnished with a slice of watermelon for a fruity punch the kids will love.
Thanks to Rowan Armstrong from Lochwinnoch School in Scotland, winner of the Active Kids Get Cooking competition, for this great recipe.