What a minger

Alright, I’m probably displaying my ignorance here, but could someone please explain to me when Sir Menzies Campbell became Sir “Ming” Campbell or even, from some commentators on the TV, Sir “Mingies” Campbell? Because I’m afraid I don’t get it. I’m sure he never used to be called that until recently. I assume it’s some sort of “Sinjun” (St John) posh bloke’s thing. What seems clear to me, however, is that one cannot realistically expect to become Prime Minster of this country if one goes around calling oneself “Sir Mingiss”. And that’s ignoring any other problems that the Lib Dems have as a credible electable force.