Ageing populations and falling birthrates have left ever fewer workers to support growing number of retirees

It has played a starring role in one of the worst periods of political turmoil in France since the 1960s. In Germany, it threatens the future of the coalition government. In Spain, thousands have taken to the streets to demand change.

The right to a decent state pension has been a central plank of the European social contract for decades, but people are living longer, birthrates are falling, and the continent’s pension systems are, increasingly, unsustainable.