As a matter of strict objective fact, Donald Trump’s trade guru is correct. Germany is the planet’s ultimate currency manipulator.

The implicit Deutsche Mark is indeed “grossly undervalued” The warped mechanism of monetary union allows Germany to lock in a permanent ‘beggar-thy-neighbour’ trade advantage over Southern Europe, inflicting mass unemployment on the victim countries and blighting their futures.

Whatever you think of Peter Navarro’s trade philosophy, he is right that Germany’s chronic, huge, and illegal current account surplus - 8.8pc of GDP - saps global demand and seriously distorts the world economy.

Let us concede that this super-surplus is an accident of history, rather than the result of a strategic conspiracy by Chancellor Helmut Kohl in the early 1990s. The German people never wanted the euro in any active sense.

The Bundesbank went to some lengths to head off the creation a ‘greater euro’ with too many ill-suited countries, constructed on the unworkable foundations that we can all see so clearly today.

That said, monetary union was never entirely innocent. The German Chambers of Commerce and Industry (DIHK) railed against the periodic devaluations by Italy and France in the various fixed exchange experiments of the pre-euro era. They were fully aware of the mercantilist advantage of fixing the D-Mark rate in perpetuity, and their influence played its part in the German acceptance of the Maastricht Treaty.

Once the euro was underway, Germany then pushed through policies in labour law and tax policies that amounted to an ‘internal devaluation’ - cutting unit labour costs in manufacturing in the single year of 2005 by 4.4pc, for example - and continued to screw down its intra-EMU exchange rate long after there was any justification for doing so. The effect was to further entrench commercial supremacy.

Large current account surpluses are invariably the result of tax policies, regulations, hidden barriers, and an overall governing structure that punishes consumption and fosters exports. Germany - for example - forces households to cross-subsidize the power costs of export industries.