What’s the origin of the phrase ‘San fairy Ann’?
A deliberate jokey corruption of the French phrase ‘Ça ne fait rien’ - it doesn’t matter.
Meaning
A deliberate jokey corruption of the French phrase 'Ça ne fait rien' - it doesn't matter.

A deliberate jokey corruption of the French phrase ‘Ça ne fait rien’ - it doesn’t matter.
Historical trend
Source: Google Books Ngrams (1920–2020).