Have the eunuchs taken over the bordello? I ask the question because the man who probably knows more about British politics than anyone else alive, the redoubtable Professor Anthony King, recently described Scottish MPs as being in effect "eunuchs". He noted that with regard to most matters that affected their constituents, they were impotent. At the same time, they retained "full virility" on matters that only affected other MPs representing non-Scottish constituencies.

We will have a General Election in the next couple of years. A Tory victory now looks a strong possibility, if not a probability. That being so, it is high time that more attention was focused on the "eunuchs", on what they do and, more importantly, what they don't do. In particular the role of the 40 or so Labour MPs who represent Scottish seats at Westminster needs to be examined as never before.

A few of these MPs are obviously doing a great deal. They include the Prime Minister, the Chancellor, the Defence Secretary and the Speaker. Unfortunately, none of these Scottish MPs with huge UK responsibilities is performing well. Indeed all four are currently regarded as being pretty inadequate. The question for them is simple: On exactly what foundation do these "eunuchs" have such considerable power beyond Scotland if they are no good at using it? It is a question that more and more English voters will be asking, believe me.

Even more pressing is the question that has to be asked about the majority of Scottish Labour MPs, almost a phantom in our lives. I'm sure many of their constituents have no idea of who they are or what they are doing. I don't altogether blame these MPs for being low profile to the point of invisibility. It is hardly surprising when, as Professor King notes, they can be of so little direct relevance to their constituents.

The current arrangements reflect a constitutional settlement which was Labour-driven. Now the time has surely come for the "Bullingdon boys" at the centre of the new Tory project, David Cameron and George Osborne, to give their full attention to this pivotal issue. But on this, if on little else, they have been strangely quiet.

Meanwhile Scottish voters could usefully ask their Westminster MPs how they spend their time, or more fundamentally, how they justify their political existence. I asked two Scots I know well what they thought their MPs did. The first said cynically: Well, they claim their expenses, and maybe they have to spend much more time on that chore now that they are being scrutinised more carefully.

The other (my wife) was both more serious and more generous. First she asked me a question: Who was our MP? I had to think for quite a few seconds before I remembered. Having made that particular point, she then said that this MP, who is regarded as a decent Labour backbencher, was always raising issues such as global poverty and what was being done about the developing world's debt mountain.

Fair enough. No-one could deny the supreme significance of such global issues. Yet - do we Scots send our MPs to Westminster to address such matters? So far I have avoided Tam Dalyell's great West Lothian question. But let me come to it this rather oblique way: What if, after the next election, Cameron has a working majority, but there are still a considerable number of Scottish Labour MPs? What if Cameron then introduces legislation to diminish drastically the number of Scottish MPs at Westminster, as he would have every right to do?

Obviously these are matters of speculation rather than fact. But the conduct of politics is partly about anticipating problems ahead. And these questions also bear directly on the present. The current Westminster dispositions are tilted unduly in favour of Scotland. Professor King has noted that though Scotland, unlike England, now has its own separate government, Scots representation at Westminster has gone down by only 13 MPs (59 instead of 72). Thus Scotland is still represented at the UK Parliament "almost as though nothing has happened."

Soon events are likely to bring that essential unfairness into focus. An incoming Tory government, with little Scottish representation but an overall UK mandate, would immediately foment grievance in Scotland. Grievance about the present arrangements is already stirring in England.

These are more than mere constitutional issues. They have a moral dimension. They concern the integrity of our sovereign parliament. They are issues that the coming man, David Cameron, has a duty to confront. Why is he not doing so?

I can see two straightforward solutions to the current mess. One would be to slash the size of Scotland's representation at Westminster. The other, which I'd prefer, would be for Scotland to become independent.