when and who invented top hat and who first worn it?

The top hat was designed and first worn by John Hetherington, a London men's clothing maker, in the 1840's. It was evident from the very start that the top hat wasn't simply any ordinary hat. The first time John Hetherington wore the hat in public, women screamed and fainted, and crowds gathered. It caused an absolute uproar which led to his arrest and subsequent fine of £50, an absolute fortune in those days. A law was also passed forbidding anybody to wear the top hat in public on the grounds it scared timid people.

The actual concept of the top hat is thought to of sprang up from the remarkably similar riding hat; a hat round and cylindrical, except flat. John Hetherington simply added to the height and size of the brim giving it an appearance so grand and statuesque it would symbolize status for all noblemen for many years to come.

http://ezinearticles.com/?Top-Hat---The-History-and-Origin&id=86976

Neither. The top hat evolved anonymously out of the attire of British coachmen.
http://twonerdyhistorygirls.blogspot.com/2011/12/english-stage-coachman.html
It's a common phenomenon that men's fashions arise either in working class wear or in sports wear.
http://cache2.allpostersimages.com/p/LRG/17/1745/7VL3D00Z/posters/john-bull-and-his-dog.jpg

Neither. A french painting shows a man with a top hat several years before George Dunnage produced the first one in england.