Hamish McRae: Let's have a little patience – things are moving in the right direction, but slowly

Economic Life: Two-speed economic growth is likely to continue, with the emerging world racing on and the developed one plugging along behind

So we carry on with Plan A. But we got from the Budget on Wednesday a sniff for what, if things go wrong, Plan B might be. It is to do Plan A but do it a bit slower. There is no disguising the fact that the economic forecasts from the Office for Budgetary Responsibility are appreciably lower than they were last October. Some forecasters, notably the National Institute, think they are still a bit too optimistic, largely because of weaker domestic consumption. This weaker growth delays the journey back to balance with, on my quick tally, things running six months behind their previous profile.

The good news is that the financial markets have taken this slight slippage in their stride. Sterling came off a little yesterday on the back of weaker-than-expected retail sales for February and there has undoubtedly been a fall-off in consumption after the rise in VAT. Actually it would have been pretty odd had there not been a fall-off in February and the two months taken together show sales still running higher than the final quarter of last year. Still, British consumers remain wary and who can blame them, given the prospect of rising interest rates, probably in May, and if not then, soon afterwards. Is this prospect for higher rates really still intact? Fiscal policy is tight so you have to have loose monetary policy. But as Spencer Dale, Bank of England chief economist, said in a speech yesterday, monetary policy would still be extremely loose even were rates to go up a bit. That is surely common sense. Insofar as lack of credit may be holding back the economy, it is availability rather than price that is the key problem. The fact that inflation is much higher than the Bank expected means that in real terms interest rates are even lower than planned. Short-term rates will remain below inflation for another 18 months at least.

In any case the AAA rating for the UK seems secure. In a special note, Moody's affirmed the triple-A rating but did warn that the continued commitment to deficit reduction was crucial to that rating. Most of us have a somewhat jaundiced perception of the rating agencies after their catastrophic performance over US sub-prime debt but I was interested in the perception of Moody's with regard to the UK. The agency makes the point that despite having a fiscal deficit of 10 per cent of GDP, the Government's plan meant that debt service costs would remain below 10 per cent of tax revenues – and this was consistent with the triple-A rating. To look at the proportion of your tax revenue going in interest seems a rather sensible way of assessing the debt burden, one that incidentally shows how much of a jam Portugal now finds itself in. So we have learnt two big things in the past few of days. One is that getting back to fiscal balance may well take a bit longer than planned. And the other is that the financial markets and rating agencies will cut us a bit of slack provided we carry on getting the deficit down as fast as we can.

But how much longer? Much depends on the trends in the world rather than what happens in the UK. The main point here is that the two-speed economic growth is likely to continue, with the emerging world racing on and the developed one plugging along behind. Data from the trade monitor, published by the Netherlands Bureau for Economic Policy, shows how export volumes have recovered at very different rates. But even though the developed countries, taken as a whole, have yet to get back to their previous peak, we are climbing steadily. So even if, as the OBR acknowledges, this recovery is slower for the UK than previous ones, there will be some sort of growth and it will be led by exports and investment.

If you want to cheer yourself up further, have a look at data from the Bank of England agents' reports on the mood of business round the country. As you can see both investment intentions and employment intentions remain positive, both for manufacturing and for services. There really is no sign of a slowdown at all there. As you might expect, the big difference between the boom years and now is that the optimism is more balanced between manufacturing and services – in 2006-07 services were much more buoyant than manufacturing. The economics team at Evolution Securities, commenting on these figures and the latest and very strong monthly CBI industrial trends survey, reckons that the upswing "remains on its feet".

This optimism is also consistent with the latest employment figures, which show that net employment is still rising, with job losses in the public sector more than offset by job increases in the private sector. What it is not consistent with is that decline in GDP reported in the final quarter of this year. We will just have to wait, and it could take anything up to 18 months, to know whether those figures are right or not.

So what should be look for in the coming months? The thing that I am most concerned about is not the pace of economic growth, which will continue to be uneven but good enough to enable the private sector to carry on hiring and investing, but government revenues. We don't know how much damage has been done to revenue-raising by the increase in income tax rates. That the 50 per cent rate may be reducing revenue rather than increasing it was acknowledged by the Chancellor in his speech and the message that it was not permanent was clearly designed to stop people adjusting their habits in response. But there is real danger that the top 1 per cent of income tax payers that account for more than a quarter of income tax revenues may already have taken action to reduce their income, and if receipts come in weak in the coming months, as they did in February, then the Treasury could be in more serious trouble than it realises.

There is no point in speculating about how people might respond. Let's just look at the revenues. If they hold up that will be fine, and if they don't it won't.

A more encouraging note to end on: when you look at the scale and range of shocks the world economy has encountered in the past few weeks it is remarkable how solid it still feels. There have been the human catastrophes of Japan and North Africa/Middle East. There are the continuing financial blows to the fringe eurozone countries, especially Portugal and Ireland. There is the still-dreadful housing market in the US and some weak durable goods orders just yesterday. Put this jumble together and you would expect there to be real concerns about the security of the world recovery. But markets have taken all this in their stride and the global business community remains quite upbeat – and it is worth making the point again that if the world economy carries on growing the UK will go on growing too.