Guido Westerwelle, leader of Germany’s opposition Free Democrats, criticised the government of Angela Merkel, chancellor, on Monday for advocating tighter financial regulation on the international stage but failing to tackle banking supervision at home.

Mr Westerwelle, whose free-market FDP hopes to form a government with Ms Merkel's Christian Democrats after a general election in September, complained that Berlin had done “nothing” to tackle Germany’s fragmented banking supervision, almost a year after the collapse of Lehman Brothers. “Those who want good European and global banking supervision should at least be able to do their homework in Germany,” he said.