“This the moment of decision. We have to stand up for what we believe and the sort of world we want to live in,” says Leonard Ihssen.

In a community centre in the town of Eberswalde, north of Berlin, the Green Party is choosing candidates for local council elections, but the meeting is a far cry from the stereotype of middle-aged political types discussing traffic management. The hall is packed, and many of those present are strikingly young.

Mr Ihssen is just 22 years old, but he is standing for nomination. He is part of a remarkable wave of young Germans flocking to the Greens in the face of growing disillusionment with the country’s mainstream parties.

“We need a vision for the future,” he says. “What is really needed in Germany and in Europe is for people to start saying what they are for, not what they’re against.”

The Greens recorded a record intake of 10,000 new members last year, making them the third biggest national political force in Germany.

Even more strikingly, the rise came at a time when most German parties are losing members: Angela Merkel’s Christian Democrats (CDU) saw their membership fall by 11,000 last year, while the centre-Left Social Democrats (SPD) fell by 5,000.