Not that, specifically, though it might be indirectly?

I’m basing it off of one of Gyles Brandreth’s yarns where he described how he dealt with abusive constituents when he was a MP.

Dear sir or madam:

Some crackpot has written me an abusive letter, and they’ve signed your name at the bottom. […]

Whether he came up with that or adapted it from something prior, I don’t know.