My Fair Lady - cockney accent

Which theatre play is My Fair Lady based on? Who is its author? Which century did he live in? Watch the scene from My Fair Lady In the scene you can hear cockney accent. Who used to speak the accent? What do cockney speakers do with letter "h" at the front of the words? What is the difference in pronouncing diphtongs? What irritates prof. Higgins about cockney speakers pronouncing "linger" and "singer"? What could you rather hear from cockney speakers instead of "ever"? Why does prof. Higgins shout at colonel Pickering?