Mrs Yellen added the usual caveats about "false dawns". Wages are barely rising. The jobs market is not yet drawing back the millions who dropped out of the system. The labour participation rate is still stuck at a 36-year low of 62.8pc, and at the lowest ever recorded for men. "The recovery is not yet complete. We need to be careful to make sure the economy is on a solid trajectory before we consider raising interest rates," she said.