An interesting decision announced on Sunday was by the Trade Union leaders of Scotland to support the “NO” campaign. One might have expected, what with the left-leaning nature and rhetoric of the independence campaigners, for trade union leaders to be supporting a “Yes”. But that ignores what trade union leaders know about union power, which is greater the higher the numbers.

Hence the joint quote from 12 union leaders that calls for Scots to reject independence and warns that “separating Scotland would damage the rights and conditions of working people across the country, and would lead to a damaging race to the bottom.” In their joint statement, the trade union leaders draw on the history of the labour movement saying that trade unions have “always believed that our strength comes from working together and organising ordinary working people across the country; building unity, not division.”

Their point is simple to explain. Companies are multinational, they operate across borders. Therefore to negotiate successfully with them unions are better off reflecting them in their multinationality and operation across borders. Independence would make that more difficult to do, but it is more the result of independence they are worried about.

The union leaders use the term “race to the bottom”, and what they mean by this is that Alex a Salmond has made it clear that he wants to attract companies to Scotland by lowering corporation tax. Unions are concerned that this will be accompanied by a reduction of protection for workers, perhaps in a different minimum wage. Companies are concerned about all types of regulation, not just corporation tax. If an independent Scotland engages in this race to the bottom with the rest of the Uk, and both start competing on reducing regulations and costs for companies, concerted union action will be needed to protect workers, and that will be easier to coordinate with UK trade unions instead of ones that have split.

How an independent Scotland will compete with the rest of the UK is going to be an increasingly interesting area for politics and economics students to study. But when competition like this exists, the effects on everyone are not to always benign. This is where unions are needed, because someone needs to look out for the needs of those who work but have little influence.