• Bernanke faces toughest time yet after week of bad news • Federal Reserve chairman’s speech will be scrutinised by markets • Committee split over ‘QE-lite’ solution to double-dip fears When Ben Bernanke addresses the annual symposium of central bankers in Jackson Hole tomorrow he does so against arguably the most challenging backdrop in his tenure as Federal Reserve chairman. At the end of a week of gloomy reports, Bernanke faces mounting expectations from markets that the Fed will step in to prop up the US’s faltering economic recovery. News of stalling business activity and dismal home sales have fanned talk of a double-dip recession at a time when all the easy options have run out.