how to address a letter to someone with title

[gjgilly]

Hi

Please can you tell me how to address the main part of a letter to someone who has a title?

If I was to write to : Sir Richard Branson or Sir Alan Sugar
or Lord Alan Sugar
Lady Margaret Thatcher

I am not sure if it would simply be : Dear Sir/Dear Mama
or something totally different like

Dear Sir Richard or Dear Sir Branson or Dear Lady Thatcher

Any help would be welcome as I would hate my letter to begin so disrespectfully. I don't like it if a letter comes to me and my name has been mis-spelt, so if I am going to write for information for my project I don't want it binned simply because the opening of the letter : Dear ? was incorrect.

Help :)

[Anglika]

Hi

Please can you tell me how to address the main part of a letter to someone who has a title?

If I was to write to : Sir Richard Branson or Sir Alan Sugar
or Lord Alan Sugar
Lady Margaret Thatcher

I am not sure if it would simply be : Dear Sir/Dear Mama
or something totally different like

Dear Sir Richard or Dear Sir Branson or Dear Lady Thatcher

Any help would be welcome as I would hate my letter to begin so disrespectfully. I don't like it if a letter comes to me and my name has been mis-spelt, so if I am going to write for information for my project I don't want it binned simply because the opening of the letter : Dear ? was incorrect.

Help :)

Addressing a Knight of the Realm : Dar Sir Richard; Dear Sir Alan

Addressing a Peer of the Realm
[Baroness Thatcher] : Dear Lady Thatcher
[Earl of Elgin] : Dear Lord Elgin