U.S. indices suffer a torrid session, with the S&P 500 posting its worst day since May while the Dow falls by more than 600 points. In Japan, the Nikkei is also down. Standard & Poor’s warns Chinese property developer Evergrande will potentially default without government support. Beijing is seen as unlikely to step in with aid, unless the risk of contagion rises. And European countries are holding emergency energy talks to see off creeping gas prices, but UK Business Secretary Kwasi Kwarteng says supply fears are overblown.