What is the difference between a “Sir” and a “Lord”?
A Sir is either a knight or a baronet. A knight is given his title by the monarch (and there are several kinds, with the 24 Knights of the Garter at the top) and a baronet inherits his title from his father or another male relative. Very, very few baronets have been created since 1964. A lord is either a peer (duke, marquess, earl, viscount or baron) or the son of a duke or marquess (like Lord Randolph Churchill). Paul McCartney and Alan Sugar are knights. The barons for life all sit in parliament, while only 92 of the 100s of lords who inherited their titles can sit in parliament. Neither title requires any land. If you wish to be a British lord, you’ll have to move to Britain and perform some form of public service to earn one, and also take out dual citizenship. Inga Stina Robson was Swedish and became a British baroness.
