Economists have been the brunt of many a joke. A particularly unflattering one tells of a chemist, a physicist, and an economist surviving a shipwreck to a small island, only able to save a can of beans.

A heated contest soon emerges between the chemist and the physicist as to how best to open the can – the former wanting to accelerate the rusting off of the lid, with a potion of salt water and various local vegetation; the latter, fearing such a process alarmingly slow, suggested propelling the can to strike a rock at such an angle as to pop the lid off; which, in turn, was seen as alarmingly risky by the chemist.

So, in defeat and desperation, they turn to the economist who, unflinchingly, suggests, "Assume we have a can opener!"

Substitute "MYEFO" for "beans", and "budget surplus" for the "can opener". That is exactly what the government did this week! Projecting a rapid return to 3 per cent real growth (stronger than our "long-run potential growth"), together with a rapid pick up in wages and inflation – aided by also "assuming" the passage of expenditure cuts they haven't been able to pass through the Parliament in the last couple of years and, hey presto – they could foreshadow a budget surplus by the end of this decade.