In the 1980s Robert Solow, an economist, remarked that you could see the computer age everywhere except the productivity statistics. Today it could be said that the revolution in military affairs, playing out in the skies, trenches and seas of Ukraine, is visible everywhere except the European defence industry. America boasts three defence-tech “unicorns”, private firms with a valuation of more than $1bn, if you count SpaceX, Elon Musk’s rocket-and-satellite company. In Europe there is one: Germany’s Helsing.
