IF, as now seems highly likely, Scotland goes to the polls next month to elect members of the European Parliament, we’ll be using the closed list voting system.

That’s one of four voting systems in current use for various types of election, which must make this country one of very few in the world to use completely different systems for each tier of elected representation.

A cynic might suggest that just about the only concrete advantage of Brexit, if it ever happens, will be to automatically cut us down to a mere three voting systems, thus taking a small step towards reducing voter confusion.

In the meantime, the good news is that the Euro voting system is considerably more straight-forward, and easier to understand, than the systems used for Scottish Parliament and local government elections.

Each of us will simply be casting a single vote for a single party. The votes will be counted, and then the seats distributed in proportion to the share of the vote each party received.

In theory, it’s the purest form of proportional representation there is, with no complexities or wrinkles such as dual ballots or preferential voting.

In practice, however, the fact that only six MEPs are being elected in Scotland limits the proportionality that can be achieved, and blatant anomalies will be particularly easy to spot when two parties receive roughly the same number of votes.

On the first occasion the system was used in 1999, the SNP took 27.2% of the vote to Labour’s 28.7%, but were allocated only 25% of the seats (two out of eight) compared to Labour’s 37.5% (three out of eight).

By contrast, five years later in the fateful European election that brought a sudden end to John Swinney’s leadership, the SNP were in a distant second place on the popular vote, with just 19.7% to Labour’s 26.4%, and yet both parties ended up with two seats out of the seven then available.

That sort of thing can happen because each seat is allocated individually, one after another, using a formula that takes into account the votes each party received and the number of seats it has been awarded so far.

Two of the most popular formulas used around the world for list systems are Sainte-Lague, which at the margins is more favourable for smaller parties, and D’Hondt, which is friendlier to larger parties.

Both formulas were considered by the Labour government in the late 1990s when proportional representation was introduced for euro-elections, but there are no prizes for guessing the answer to the question: “So what was it that first attracted you to the D’Hondt formula, Mr Blair?”

D’Hondt divides a party’s vote by a number that is one greater than the number of seats it already has in the bag.

So, if by the time the sixth and final seat is being allocated, the two most popular parties already have two seats each, both parties’ votes will be divided by three, automatically restoring whatever lead the first-placed party had over the second-placed party to begin with.

There’s an element of chance involved in whether those parties will happen to be in a straight fight for the final seat – if they are, the question of which party ends up with the most seats overall will effectively be decided on a first-past-the-post basis, as happened in 1999.

But if they’re not, the winner of the popular vote may have to settle for a purely moral victory, as was the case for the SNP in both 2009 and 2014, when they finished with the same number of seats as Labour.

IT could be a different story this year. If the SNP can come even vaguely close to replicating the high 30s and low 40s vote share they’ve been scoring in recent opinion polls for Holyrood and Westminster, they’ll have an excellent chance of finally winning the third European Parliament seat that has agonisingly eluded them on multiple occasions.

Even their disappointing 29% of the vote last time around was enough to come within a relative whisker of pipping David Coburn of Ukip for the final seat. It may seem counterintuitive that a proportional system could conceivably give a party 50% of the six seats on the basis of less than one-third of the vote, but that’s perfectly possible thanks to D’Hondt’s helping hand for larger parties.

Unless a low turnout throws up a freakish result on the popular vote, much of the seat allocation is easy enough to predict – the Tories should take exactly two seats (a gain of one), the SNP should take at least two, and Labour at least one. that would potentially leave the SNP, Labour, the Greens, the LibDems, Ukip and possibly even Nigel Farage’s new Brexit party in a multi-party dogfight for the one remaining seat. Who wins? You decide.