The number of working Americans turning to free government food stamps has surged as their hours and wages erode, in a stark sign that the recession is inflicting pain on the employed as well as the newly jobless.

While the increase in take-up is often attributed to the sharp rise in unemployment – which on Friday hit 9.7 per cent – the Financial Times has learnt that some 40 per cent of the families now on food stamps have “earned income”, up from 25 per cent two years ago.