Thursday 21.30 BST. The S&P 500 index and US Treasuy yields experienced their biggest decline since the financial crisis, as global investors shunned risk after central bankers failed to stem fears of rapidly slowing growth.

The day’s move was kicked off by a steep fall in the yen after Tokyo intervened to weaken the currency in the latest move by a central bank to combat the impact of market turmoil. It was accelerated by news that the European Central Bank would return to the market to buy bonds issued by troubled debtor nations.