One way of mapping the difference between electoral systems is to plot them on a continuum between fairness and clearness. The two qualities tend to have a negative correlation. Countries in which each individual vote can plausibly be said to have some bearing on the outcome – i.e. countries with a system which is to some extent proportional – are fairer. But they often end up with coalition governments. Countries with some version of first-past-the-post tend to have clear electoral outcomes which in effect disregard the relevance of many votes. The German, Italian and Israeli (for instance) electoral systems are fair but not clear; the British electoral system is the epitome of a system which is unfair but brutally clear.

In theory. Not this time, though: we are heading for an outcome which might well be neither fair nor clear. The resulting constitutional muddle could rival that car crash which could be heard in the background yesterday while Peter Mandelson was giving an interview.

The famous precedent for this is the 1974 hung Parliament, but I was chatting to a French-Canadian journalist yesterday who pointed out that there are more recent examples to hand in Canada’s very similar electoral system. They too have one of those clear-unfair systems, designed to give uncomplicated power to the winning party; but the last three elections have returned minority governments. The reason is the rise of the Bloq Québécois, the separatist-leaning group which has hoovered up a significant share of the vote since its first electoral showing in 1993. The Bloc is now a permanent third force in Canadian politics, and is doing a good job of preventing the two historic main parties, Liberal and Conservative, from forming majority governments. The result is that the governing party has to govern in a hand-to-mouth way, forming majorities issue-by-issue as it goes along. This sounds exhausting, but it apparently works, and the electors’ dislike for having elections every two minutes prevents the opposition from bringing down the government just for a laugh whenever they feel like it.

This could be relevant to our election. Discussion here is focusing on the idea that the Lib Dems will hold the balance of power. If the Tories get within sniffing distance of a majority, however, they might well not need Lib Dem help. In the last General Election, the SNP and Plaid Cymru won nine seats between them; in Northern Ireland the Unionist parties won ten seats and the Nationalist parties won eight. So any Tory result over 300 seats would create possibilities for serious horse-trading with these regional parties and no need to involve the Lib Dems at all. No wonder Alex Salmond has been looking so cheerful.