Just over a week ago I had lunch with three economists, all with more than a passing interest in construction. Oddly, perhaps, for a group of economist there seemed to be a consensus, well at least on one topic.

If construction is heading for recession then the Government is wise to spend to ease the depth of it.

This is a view I broadly share. So, Mr Darling's reported decision to bring forward budgeted cash for construction work should, you'd think, hit the spot for me.

Well it will, if the money is directed wisely. If not I fear it could do as much harm as good. Or, put another way, many of the benefits of a public sector boost may be lost.

As I see it, the Government needs to recognise broadly three things about construction. Each should be obvious to ministerial advisers, but sadly there are no guarantees.

The first is that construction is not one coherent industry, although the various elements do share from a pool of common resources.

The second is that not all sectors of construction are set, as we stand now, to see a recession. Some may see growth. Infrastructure, for instance, looks to have pretty buoyant near-term future. And, if we accept the latest Experian forecast, take house building out of the equation and workload is set to remain above 2007 levels.

The third point is that, in some sectors in some parts of the country, the industry remains stretched, or at least it was up until pretty recently. Construction is at a historically high level of output and it was not that long ago when skills and management shortages were pretty much top of the agenda.

Given the above, the Government needs to target any stimulus carefully to the sectors and regions that need and can accommodate it. It also needs to target the sectors where spending will produce the best rewards for the nation as a whole.

The Government needs to have clear objectives in mind for targeting its funding and it needs to ask difficult and critical questions before launching into a surge in spending.

Here's just one thorny issue.

The benefit of buying construction when it is relatively cheaper is pretty evident. But the benefit of maintaining the livelihoods of local construction workers is, in my view, significantly more important, not least as this helps reduce unemployment benefit payments.

Construction has been obliged to rely on the talents of Eastern Europeans to meet demand in recent years. Their arrival provided huge relief to the industry. The departure of those who plan not to stay long-term presents some concern.

So the loss - to unemployment or other industries - of yet more British construction workers would further tear apart the local skill base ahead of an eventual upturn in work, when there may no longer be a guarantee of relatively cheap, highly-skilled labour from abroad.

It would be ironic, not to say politically explosive in the light of the recent comments by Immigration Minister Phil Woolas, if extra public funding was perceived as a beacon to attract in migrant labour to meet the needs of one overstretched part of the industry while other parts of construction, or indeed other industries, were shedding jobs aplenty.

Construction can play a huge role in taking some of the pain out of what now looks like an inevitable recession. It would be excellent if the whole nation saw its worth when the good times return.