"If you had a fully blown recession triggered by Europe and another credit crunch it's not impossible to see borrowing a couple of years down the track exceeding the £156 billion which we had in 2009-10."
The Government borrowed £137.1 billion in 2010-11, equivalent to 9.3 per cent of GDP.
The OBR projects that the deficit will fall to £127 billion this financial year before dropping to £120 billion in 2012-13 and £79 billion in 2014-15.
Shaw also warned that if the deficit shoots up due to a return to recession in the UK, the Government's borrowing costs could rise, opening the door to a sovereign debt crisis.
"If you're talking about the worst-case scenario, it's quite feasible that you should be looking at higher yields."
Andrew Goodwin, senior economic adviser to the Ernst & Young ITEM club, also warned that public finances risk being thrown into chaos by low growth.
"If growth falls short there is a major problem and it does have big implications for the targets further out," he said.
Independent