This is a cute and wacky little item!
Here's a Sonic mini-schoolbag! This micro bag is likely to be something more like a coin purse or tiny item carrying case. It looks to be about 4 inches high, tops. You could wear it, if you put the 'shoulder straps' through a belt, or possibly attach it to a real school bag.With the fun Sonic design, and attention to detail (quite similar to a full size bag) this is a clever and cute little Sonic collectable.

This is by Dekker toys and was available in 1991, which is quite early on the Sonic Timeline. It could be won/gotten at an amusement park somewhere in the England area.