Used in direct address to peers of the realm, usually now excluding dukes and the Lords Spiritual.
Used in direct address to the Lord Mayors of certain important cities, including London and Canterbury.
Used in direct address to bishops, particularly Anglican ones.
Used in direct address to certain judges, particularly High Court Judges and above.
Posh.
A person (especially a student) with a posh accent who looks down on those who are "common".
An expression of surprise.
An exclamation of encouragement.
An expression of admiration.
An expression of frustration or anger.