It is just as well to be aware that any controversial proposition can be improved by an economic impact assessment and, conversely, that any proposition can just as neatly be dished by such an assessment. This is not to say that professionally executed assessments are utterly malleable and can be made to fit any given situation. Nevertheless, there are ways of doing such things and in the case of the latest examination of the issues around the completion of the final 4.8 mile stretch of the M74 motorway in Glasgow, the most appropriate reaction to the projected job losses if the project does not go ahead is a loud and resonant horse laugh. The pressure group in favour of completing the motorway has its hands on an assessment which suggests that more than 6000 jobs could be lost to the west of Scotland if the projected south side link between the M74 and the M8 is not built. In casting doubt

on its conclusions on employment there is no intent to disparage the work of the Scottish Enterprise consultants who compiled it. But their methodology remains unknown and if it consists of a vox pop of employers within the surrounding area of the proposed link with off-the-cuff responses multiplied by the number of businesses interviewed we remain unconvinced.

One of the chief supporters of the scheme claims that at long last we are all in possession of a comprehensive economic study which provides a factual basis for what will happen if the link is not built. Note those confident, affirmative words: ''a factual basis for what will happen''. It is nothing of the sort and those who are most anxious to see the link built merely do damage to their case by resorting to possible effects which are presented as future facts. The irony in all this is that the case for completing the link between the M74 and the M8 is already established and makes excellent sense as long as a lengthy list of environmental precautions are adhered to rigorously.

It is, and always has been, a nonsense that the completion of the last small section of the M74 through the South Side of Glasgow has been postponed for so long. Each quadrant of the city would be linked thereby and there is no need for an economic impact assessment to demonstrate that many South Side opportunities would be unlocked by completion. The plan was stalled originally because of planning objections but a lot of the original objections have disappeared over time and the amended plan for the link thankfully will not increase pressure on the Kingston Bridge. Those who want the link completed are, therefore, pressing on an open door as far as the practical arguments are concerned. The politics of it all is a different matter. In the South Mr Prescott is poised to unleash his car-bashing extravaganza on us in the summer; surely an inspired way of losing votes. In Scotland a review of

all road-building projects is under way. It, too, will be delivered in the summer and at the top of its list of projects should be the M74's missing link.