According to the Chancellor, the UK will grow at between one and 1.5 per cent this year - more than forecast by both the City and the Bank of England - and at between 2.25 and 2.75 per cent next year. In 2001, the economy will expand by as much as 3.25 per cent, he said, considerably faster than its long-term trend rate.
Independent economists were divided over Mr Brown's forecasts. Many argued that the Bank of England's recent string of aggressive interest- rate cuts made it more likely that he would hit his growth targets.
"His forecasts don't seem out of line with reality," said Ian Stewart, UK economist at Merrill Lynch. Others noted that recent signs of economic improvement - such as Monday's news of a rise in manufacturing output - seemed to support Mr Brown's optimism.
Other analysts, however, called the Government's forecasts unrealistic. Even the Treasury's most pessimistic estimate for 1999 growth - one per cent - is almost double the consensus City forecast of 0.6 per cent. It is also at the top end of the Bank of England's expectations. In its last economic forecast in February, the Bank predicted 1999 growth would slow to between 0.5 and one per cent.
Mark Wall of Deutsche Bank, which is among the most pessimistic of City forecasters, said: "He may be selling the public short by offering these figures. To get one per cent growth out of this economy would be miraculous."
Mr Wall believes that growth will stall this year and that the economy will suffer a short recession in the first six months of 1999 before bouncing back in the final quarter of the year.
In common with many other forecasters, the Chancellor believes that net trade will continue to drag down economic growth and that the outlook remains tough for Britain's manufacturers. Yesterday's forecasts contain substantial downward revisions to predictions for both export growth and manufacturing output.
Mr Brown now believes that manufacturing will contract by between minus one and minus 1.5 per cent this year, before recovering in 2000. In November, his range was between minus 0.25 and 0.25 per cent.
Exports are now forecast to grow at between 0.25 and 0.75 per cent, compared with between 2.75 and 3.25 per cent in November. As a result, the UK's current-account deficit is set to soar to pounds 10 billion in 1999, according to this latest forecast. The Government said: "Net trade and hence manufacturing output were weaker than expected in the fourth quarter of 1998."
Michael Saunders, UK economist at Salomon Smith Barney/Citibank, said: "If anything, the risks to export growth are on the downside. We had such a weak performance last year that it seems reasonable for exports to remain soft."
Also in common with other forecasters, the Chancellor believes that recent rises in business inventories present a significant downside risk to growth. The latest Treasury predictions are that the running down of company stocks will knock as much as 0.25 per cent from economic growth both in 1999 and in 2000.
Mr Wall at Deutsche commented: "Most of the growth in the fourth quarter of 1998 came from stocks and investment. We have a stock overhang problem. Companies will have to run down stocks before production can really pick up again."
Where Mr Brown is far more optimistic than almost every other forecaster is in the areas of household consumption, investment and government spending. Substantial upward revisions to his forecasts in all these areas have allowed the Chancellor to reaffirm his aggregate predictions for economic growth, despite the deterioration in both net trade and manufacturing.
On household consumption, the Chancellor is predicting a growth rate of between two and 2.5 per cent this year, compared with the City consensus of 1.5 per cent. On fixed investment, Mr Brown is arguing that the growth rate will be between two and 2.5 per cent this year - more than double the City consensus. Few independent forecasters found themselves able to agree with this.
Mr Saunders at Salomon Smith Barney/Citibank said: "Survey evidence suggests that the overall growth rate of business investment will slow sharply this year and may well turn negative, although the growth rate of government capital expenditure is likely to increase sharply."
On government expenditure, Mr Brown was again more upbeat that independent forecasters, although he, of course, had the benefit of inside knowledge. The Treasury is predicting government spending will grow by three per cent this year and by 2.25 per cent in 2000.
"General government investment is expected to contribute around 0.25 percentage points to gross domestic product growth in each of the next three years," the Treasury said.
There were fewer surprises in the Chancellor's inflation forecast. Mr Brown predicted that the underlying rate of inflation would hit his 2.5 per cent target in both 1999 and 2000, although, as in November, he admitted there was a possibility of inflation undershooting target at some point this year.
The Chancellor told Parliament yesterday: "We took decisive action in 1997 and 1998, and, as a result, inflation is under control."
Analysts predicted that inflation would probably be lower than predicted by the Chancellor, although few were surprised at his forecasts. Had Mr Brown forecast inflation at above or below target, it would have been perceived as implicit criticism of the Bank of England's interest-rate policy.
The consensus City forecast is for underlying inflation to be at 2.2 per cent both at the end of 1999 and at the end of 2000. Some believe inflation could fall as low as 1.5 per cent.