In December 1997 the Minister for Finance predicted a Budget deficit of £89 million and, 12 months later, he turned in a surplus of £747 million. The miscalculation amounted to £836 million, an extraordinary mistake in anybody's terms.

The monumental nature of the error has, since then, been matched by the failure of both Charlie McCreevy and the Department of Finance to explain precisely what went wrong or to take disciplinary or remedial action as a consequence.

The only obvious signal of embarrassment was found in the decision by Mr McCreevy to absent himself from last week's official briefing on the end-of-year Exchequer returns. Even his thick skin wasn't up to the exercise that might have been anticipated in the circumstances.

So Michael Tutty, second secretary of the Department's general budget and economic division, was sent out to blind journalists with figures and to play ring-a-ring-a-rosy around the Exchequer returns.

During that process, it was discovered the Department's miscalculation might have been even more horrendous than admitted. A black hole, entitled the "ways and means" accounts, was found to contain a further £830 million for various authorised projects and services which had not been drawn down. Some £100 million of that related to a technology fund for schools, which was to have been spent in 1998, but wasn't. Other details weren't available.

The size of the financial overhang was huge when you consider that, by the end of 1997, the ways and means account contained only £270 million, compared to £830 million in 1998. And it led to speculation that Michael Somers of the National Treasury Management Agency may have struck close to the bone when he originally estimated the Government surplus at £1.3 billion.

The most disturbing aspect of the affair is the pattern of underestimation that emerges. For the past six years the gap between the Department's revenue estimate and the outcome has grown rapidly. In 1992 the gap was only £48 million, but this grew to £357 million in 1994, £520 million in 1996 and £957 million in 1998.

Given such poor predictions, Government accounts have become practically meaningless. But because the figures have been on the positive side of the line, the Department of Finance glides blithely along. And international financiers take its figures with large dollops of salt.

Already within weeks of the December Budget, Mr McCreevy has admitted that his surplus figures for 1999 may have been underestimated. So what is the point of the Budget? Is the "think-of-a-number" exercise conducted by the Department of Finance only designed to hold down spending and flatten public expectations? And, if it is, surely that is the function of government?

There are those who attribute the behaviour of the Department to an ingrained culture of caution; to the dead hand of bureaucracy that has stifled innovation for decades by refusing to take risks or to spend public money.

It would be wrong to blame the Department for past government failures. But its parsimonious approach has given the State a seriously inadequate infrastructure which is unable to cope with demand. And, rather than spend part of last year's surplus on a crash programme of modernisation, it has chosen to pay off the national debt.

Worse than that, it has dragged its heels in encouraging and facilitating public-private partnerships that would invest in infrastructure. Nine months after the Government gave the go-ahead for road projects to be funded by the private sector, the Department is only now setting up the necessary planning unit. The lead-in time for such projects may be five years or longer. At this rate of progress, we can anticipate State-wide gridlock and a bumpy economic landing.

Caution and parsimony may be useful attributes in a time of recession. But there is a tide in the affairs of men . . .