We get US telly here in the UK, and I've seen Gordon Ramsey called "Chef Ramsey" on American versions of his telly programme.

Likewise US reporters always refer to "Prime Minister Cameron", whereas we'd just use Cameron.

You lot also refer to strangers with a respectful "Sir" or "Ma'm". You also use Mr. where we'd simply use the surname.

There may be other examples..

Does anyone know how come the British are generally more informal when referring to others (bar specifically those with Knighthoods or medical Dr.s or University Profs), and why the US are more formal?
Where does this cultural difference come from?