I was thinking the exact same thing the other day (reminiscing my childhood, got nothing better to do). I don't actually ever remember one bursting though, it tended just to dribble out. Gorgeous though.
I used to love them too. They've stopped making them now but there are similar bursting bugs style sweets inside packets of Rowntree's Randoms i.e. gummy sweet with a liquid centre so if you need a bursty fix then I recommend those.