What do pilots in Paris have in common with doctors in London? They're part of a rising tide of middle-class activism that's sweeping across Europe as austerity measures start to cut the continent's better-off more deeply.

Support for left-wing causes in Europe has been steadily on the rise since the credit crisis seven years ago, particularly in countries like Greece and Spain which are chafing at the reins of bailouts accompanied by austerity measures. Yet the continent's middle classes have arguably been less affected by cost-cutting than the lower-earners.