The next prime minister will have to find "many more billions" of pounds to help households pay soaring energy bills, the head of a highly influential think tank has warned.
Paul Johnson, director of the Institute for Fiscal Studies, also said struggling public services will need more investment after the Bank of England predicted the UK would be plunged into the longest slump since 2008.
Sources in the Liz Truss camp did not deny that her planned emergency budget could come as early as September 21, as the dire state of the economy becomes the main issue in the race for Downing Street.