The main salesman for the US administration’s efforts to deal with the financial crisis described the Federal Reserve plan to commit a further $800bn of taxpayers’ funds to another attempt to revive credit markets as a “great investment”.

Stepping up before the cameras at a Washington press conference on Tuesday, Hank Paulson, Treasury secretary and chief proponent of the Bush administration’s dizzying range of responses to the crisis, argued that the liquidity injection was necessary to nudge conditions closer to normal in the markets and restore lending to ordinary consumers at realistic rates.