Hello!
We had a great debate about this in the office this week. My immediate boss (the hard headed and arrogant type) insists that when the addressee of a letter is a woman, I begin the letter with:
***
Madam
We would like to thank you for your letter....
***
However, the Head of our branch remarked that "Dear Madam" should be used instead as it is more polite.
My boss snorted about this (behind the Head's back) and insisted that I keep "Madam" (without the dear), stating that using the dear would be the incorrect and impolite way. I googled this issue and as far as I am seeing "Dear Madam"
is the
normal standardboth in American English and British English (we used British). Although I am condemned to follow the rules dictated by my boss, I would really like to know how wrong he actually is

Can someone tell me which is the most correct and most polite solution? Please provide details and sources on why you think so.
Many thanks for all replies!