Germany's Chancellor Angela Merkel once said she wished "for nothing more than a free-trade agreement between the USA and the EU". But, to the dismay of many in Brussels and Washington, Germans are now taking a very different view.

Europe's biggest exporter is becoming one of the most vocal opponents of the world's biggest trade deal. A transatlantic pact would create a market of 800 million people and allow Germany to sell more of its luxury cars, trains and chemicals in the United States, an attractive proposition for an economy that has faltered in recent months.

But in a twist that few officials expected, European concerns about the threat to food and the environment have found their strongest voice in Germany, amplified by the country's influential Green party, as well as anger at reports of US spying.