Wolfgang Sch?uble, Germany's finance minister, has warned that the financial markets are “out of control” and called for “effective regulation” to ensure a properly functioning market, writes Quentin Peel.

In an interview with the Financial Times, Mr Sch?uble said markets would not work properly “if the risks and rewards are completely unbalanced”. He called for the standardisation of products, regulation of over-the-counter transactions and measures to improve transparency “for all market participants”.

He also threw his weight behind new calls for a global financial transaction tax, arguing that it should be discussed “in an unbiased way” at the June summit of the G20 economies in Canada. If it was not agreed, the European Union should consider going ahead on its own, he said.