When Mehdi Biria and his family upped sticks from Iran in 1982 and moved to Heidelberg in south-west Germany, he did not guess that within 20 years he would be the owner of Europe's third biggest bicycle manufacturer - less still, that three years later the family business would have been snapped up by an American "locust".

The "locust" - in the words of Franz Müntefering, Germany's private equity- and hedge-fund-hating deputy chancellor, was Lone Star, a Dallas-based fund that has spent much of the past three years buying up the bad debts of the country's banks.