Mark Carney should ignore the genuflecting flunkeys in pink tailcoats when he arrives on his first day at the Bank of England’s headquarters on Threadneedle Street. This is no gentleman’s club; it is a political snake pit.

The Governor of the Bank of England is point man for regulating the masters of the universe – the investment bankers who run the financial dealing rooms in London, the heart of the global financial system. Mr. Carney has already proved his mettle, in his role as chairman of the international Financial Stability Board, by seeing off the banking attack dogs – notably Jamie Dimon, the JPMorgan Chase & Co. chief who didn’t like the regulatory collar being gently lowered over his head. But that doesn’t make the challenges of his new job any less.