A Treasury spokesperson said: "That our national debt has reached more than one trillion pounds simply shows the unsustainable level of spending this country built up over the past few years, and shows why it is critical for our nation's future that we deal decisively with the deficit."
Vicky Redwood, senior economist at Capital Economics, said the overall debt level was "a reminder of the enormity of the challenge that still lies ahead to get the public finances back on a sustainable footing".