expressions - Stereotypical, recognisable, educated version of "gosh"

Is there an expression like "gosh" that a stereotypical upper-class British character would say for expressing surprise?

I've thought of "parbleu", but it being a loan word from French, it doesn't sound right as a stereotypical English expression.

I would avoid "My Lord" because of possible moral implications with the reader.

Note: it should be easily recognisable by a non-English audience.

Is there such an expression? Thanks!