Functional illiteracy may be less jarring than absolute illiteracy, since it allows for minimal competence in reading and writing. But the implication that these levels are so low that people are effectively excluded from many areas of life is severe. This raises difficult questions. Who is to say what counts as functional and what does not? The term is dripping with value judgments. So is it worth delving deeper to see if anything resembles what might be called civic literacy?

I believe it is, though I’m well aware that the term has some problematic connotations and may need replacing. Public participation needs all the help it can get. Cynicism, apathy and corruption go hand-in-hand. But active citizenship requires a level of understanding if it is to be more than prejudice dressed up as participation.

Notice I said understanding. I would argue that one dimension of civic literacy is the understanding that comes from experience, rather than instruction. This means that people will form opinions as a result of direct contact with the issues or institutions they are talking about. I once offered a minimalist national adult curriculum: that everyone should have visited a slaughterhouse, a long-stay mental institution and a prison as adults, preferably early enough for it to have an effect on their attitudes. The effect would not be the same on everyone; but the direct physical contact with these institutions would do more than several documentaries and a bundle of books.

By this criterion I am not literate - and I suppose that the chances of arranging a visit to slaughterhouses these days are slim. Certainly I know that on my first visits to prisons, which was by chance (and voluntarily) the major impact was through my nose and ears - the smell of urine and institutionalised food, the clanging of metal doors. The point of this idiosyncratic trio of institutions is to consider how we might get closer to a useful understanding of civic literacy on a broader scale.

There might be at least three major areas where a citizen might be expected to have some understanding. What we can try to do is set out a rough framework, within which people can debate what actually matters and set their own priorities.

I suggest that the economic, environmental and political spheres are cardinal. If we take the second of these, this might mean that official and unofficial bodies with a stake in the environment define what are basic levels of understanding achievable by 80 per cent of adults. The understanding would be a matter of grasping the issues, and ways of learning would have to flow from this. The challenge to the groups concerned would be to establish priorities, what really counts.

The spheres intersect. You cannot understand environmental issues without a grasp of economics; nor can you understand the economics of the business you work in without knowing something about the politics which allow it to operate as it does. But this doesn’t mean that the three cannot be meaningfully disentangled.

Sounds too much like a national curriculum? Perhaps. But the idea of a whole series of debates on the notion of civic literacy without anyone having the right to impose their views on the populace has its attractions. Let me put it negatively: if we cannot offer any indication of what a well-informed citizen looks like, we have a curious understanding of democracy.

On the Move, the adult literacy campaign two decades ago was a tremendous success. It opened up experiences for many who had been excluded. Even getting the notion of civic illiteracy into common parlance might do quite a lot to create a similar momentum.

Professor Tom Schuller is director of the centre for continuing education at the University of Edinburgh