dialogue

This line is often used in TV shows, usually when a character is trying to use an english accent. He will use a british slang and say something along the lines of

'ello gov'nor!

Two examples from the top of my head, although there are a lot more:

'ello gov'nor!

In Community S03E16, Troy is busy and so Abed has to use the dreamatorium with Annie, who is supposed to play temporary Constable Geneva. She does it all wrong however, jumps out and says in a bad british accent:

Oy gov'nor, quantum spanner innit [..]

So it seems to be used as a gag to show that someone is really bad at British accents. Here's my question:

What's the origin of this line and why is it so popular in shows/movies?

Is it a reference to a famous movie scene? Or something that is just a common gag among Americans?

Bonus points if you can name the first show or movie where it was used.