Reports from Westminster indicate that the Prime Minister has been convinced by studies saying that having a common minimum wage _ currently £5.35 an hour, rising to £5.52 in October - is uneconomic. Since the cost of living varies from region to region, it is argued, the minimum wage should reflect these differentials.

But the effect of such a fundamental change, in minimum levels which have always been fixed nationally, would be enormous. In Northern Ireland it would be an acknowledgement that ours is a low-wage economy, needing low-wage jobs, and it would breach the principle that nationwide wage levels should be the same, regardless of where one lives.

The Government might argue that in some jobs there is already an acceptance of "weighting" in London to allow for higher living costs. This can be done through the existing system, but raising the minimum wage to £7 there would only attract more low-wage migrants from elsewhere, living in poor conditions.

Just as important, reducing the minimum in regions like Scotland, Wales and Northern Ireland would further reduce the incentive for many people to work. The difference between what they can receive in benefits and wages is already too small, for those with few qualifications, and Northern Ireland has the highest percentage of working age adults in the UK who are not in the labour market. More would join them, if the minimum wage level were lowered.

Economists might argue that lower minimum wage levels would be attractive to investors, but proof would have to be produced. Living costs are levelling out, as mortgage rates rise, and the overall effect would be to reduce the living standards and expectations of everyone, except those on guaranteed national rates in public service jobs.

Not surprisingly, members of the Stormont executive, as well as MLAs and trade unions have expressed outrage at the proposal, which the Government cannot ignore. One benefit of having devolved assemblies, here and in Scotland and Wales, is that they can fight proposals that would place them at a disadvantage, compared to more prosperous areas like southern England.

Another effect of the proposal, introduced without consultation, is that it has united politicians across the political spectrum, from DUP to Sinn Fein. If Mr Brown wants to make the Northern Ireland economy more competitive, it is not by lowering the minimum wage, but by cutting corporation tax to the Irish level of 12.5%.