Postcard from... Potsdam

Germany's Greens are proud to be Europe's most powerful environmentalist party but as is often said: pride comes before a fall.

The Greens have fallen on their noses in the former garrison town of Potsdam, outside Berlin, where their recently dismissed regional treasurer in the state of Brandenburg is on trial for stealing thousands from party coffers and allegedly using the cash to fund an extensive prostitution racket.

This is new ground for a party which likes to think itself morally superior to its political rivals. Christian Goetjes, 34, is accused of siphoning off well over ¤250,000 (£201,000) of party money into his own account from 2009 onwards.

Early on in his trial Goetjes claimed to be a Robin Hood figure who helped impoverished Bulgarian prostitutes beat heroin addiction, pay off credit sharks and fund badly needed medical attention. He told judges he was on social security, still living with his parents and had stolen the cash to help them.

But new police evidence now available to the court has suddenly revealed that Goetjes had another side. It shows he ran a Berlin escort agency and internet prostitution site, which involved him personally escorting prostitutes to their clients and haggling over the price. Goetjes is said to have always kept half the money for himself. He is alleged to have been still running his prostitution racket during the opening of his trial.

In an attempt to patch up relations with his former employers he has offered to pay back ¤65,000 (£52,000). But the latest disclosures have persuaded the Greens to reject the idea. They now want Goetjes to return all their missing funds.