A Republican politician has been forced to resign after footage emerged of him shouting racial slurs in a US television show.

Jason Spencer, a Georgia state representative, was duped by comedian Sacha Baron Cohen into dropping his trousers and shouting the N-word in an apparent attempt to deter terrorists.

Mr Spencer initially refused to quit after the show aired on Sunday, calling it a "ridiculously ugly episode" .

He has come under mounting pressure to stand down with several major US networking showing the embarrassing footage on prime time news shows.

David Ralston, the Speaker of Georgia's House of Representatives, told CNN Mr Spencer's actions and language were "reprehensible", adding: "Georgia is better than this."