There has been a rumor going around that Dudley Coutts Marjoribanks was not Lord Tweedmouth but rather Baron Tweedmouth.
Well, the fact is that he was both and referred to as both.
He was a part of the House of Lords in parliament (Lord) and he was a land owner (baron.)
People get confused when someone who owns a great amount of land is referred to as Baron. They think of that as a title like Lord but is just referring to the land owned.
My great grandfather was a baron but he was not part of royalty or any praliament. He simply owned quite a bit of land.