When Angela Merkel, the German chancellor, announced the appointment of Jens Weidmann, her economic adviser, to be president of the Bundesbank in February 2011, the shock through the German establishment was palpable.

It was not just that the lanky, boyish-looking 44-year-old – the youngest president of the central bank in its history – did not fit the grizzled image of his predecessors. The real concern was that, as one of the chancellor’s closest associates for five years, he would be unwilling or unable to uphold the autonomy of the institution that incarnates German monetary discipline.

Handelsblatt, the business newspaper, published a scathing cartoon of a matronly Ms Merkel placing a doll-sized Mr Weidmann in a box marked Bundesbank. Its accompanying editorial warned that the “Holy Grail” of the central bank’s independence, laid down in its founding articles, was in danger of being left without a keeper.