These are the European Smarties, not the american kind[1] which are more of a flavored chalk than a chocolate covered by a candy shell.
1. http://caffeineplease.typepad.com/caffeine_please/images/200...
1. http://caffeineplease.typepad.com/caffeine_please/images/200...
Fizzers is the British name for the tablet sweets, and the original one. They were renamed Smarties when they were imported to the US, like how Harry Potter was renamed!
http://idsgn.org/posts/parallels-fizzers-rockets-smarties/
M&Ms are also just a copy of the existing chocolate Smarties.