Rory Stewart is running for London Mayor as an independent. That makes voters’ choices ten times harder and could result in carnage in the election next May.

That Stewart would be forced to abandon his current seat of Penrith and the Border in Cumbria was pretty clear. He had been deprived of the Conservative whip by Boris Johnson (although he remained a member of the party) and so would not be able to re-stand as a Conservative in the seat he has represented for ten years. The seat had previously been represented by David Maclean and Willie Whitelaw and is unlikely to be anything other than Tory after the next election. Some suggested he might seek revenge by standing against Boris Johnson, but Stewart has chosen instead to throw his hat into the ring for the London mayoralty, a position formerly held by the PM.

So why does this make things especially difficult?

The problem is that the London mayor is elected by a voting system known as the Supplementary Vote (SV), often described as the worst of all worlds.

Using SV, voters are faced with a ballot paper which asks them to mark an X for their first choice in one column and a second X in a second column for their second choice. At the count, the first choice votes are added up and if a single candidate has more than 50% of the votes cast then they win. But if they don’t then the top two vote getters are put through to the second round and the second choice votes on the ballots cast for all the other candidates are examined and any votes for either of the top two are added to their total. The candidate with the most votes after this is done is declared the winner.

Here’s the problem. If you want to ensure that your vote counts then you need to know (or guess) which two candidates will make it through to the second round (there will surely be a second round in London). You can then pick which of those two candidates you prefer (or least hate). The good news is that you can safely cast your first preference for whoever you genuinely like on the full ballot list, even if you suspect they have no real chance of winning. The bad news is that everything after that is guesswork.

So who will make it through to the second round? At the moment I wouldn’t like to guess. Clearly the current mayor, Sadiq Khan, has a good shot. He is the Labour candidate in what is historically a Labour city. But remember that in the first London mayoral election the official Labour candidate, Frank Dobson, was not in the top two. So it can happen. And there are now three other strong candidates. Shaun Bailey is the Conservative candidate, Siobhan Benita is standing for the Lib Dems (who topped the poll in London in the European elections) and now Rory Stewart. Add in the Green Party and Brexit Party who have smaller but significant levels of support as well as countless fringe and independent voices and it all becomes very complicated.

Your first choice is not going to be a wasted vote but your second choice, and therefore your ballot as a whole, could well be.

Here’s how it works for my particular case:

I have a strong preference for the Lib Dems. Of the rest, I have some sympathy for the Green Party and I like Rory Stewart despite him being in favour of Brexit. I would prefer Sadiq Khan to Shaun Bailey. So I will cast my first preference for Siobhan Benita. If she does not come in the top two then I want my vote still to make a difference. If I cast my second preference for the Green candidate it will likely be wasted. I am willing to bet that Sadiq Khan will be in the top two but who will it be against. If it is Shaun Bailey then I would cast my second vote for Khan. If it is Stewart then he would get my choice rather than the Labour candidate.

Add in the fact that many parties will try to convince voters to just cast a first preference in the mistaken belief that anything else could damage them and you are in a right muddle.

There are two possible solutions to this mess.

The first would be to move to a proper two round system such as is used in France. After the first round, all but the top two are eliminated and a second vote is taken a week or two later with just the top two from the first round on the ballot paper. That way, voters can have a free choice without the risk that their vote will go to someone already eliminated.

Alternatively (pun intended), move to AV – the Alternative Vote. Here voters number all the candidates in order of preference – 1, 2, 3 etc until they cannot decide between the remainder. Candidates are excluded in turn from the lowest vote getting and their ballots distributed according to the voter’s next preference until one candidate has the support of more than half the voters. It may be that it is your fourth preference that is counted, but your vote will not be wasted. 

In my example I can safely vote:

1. Lib Dem
2. Green
3. Stewart
4. Labour
5. Conservative

and know that if it comes down to a final round choice between Khan and Bailey then my choice will still matter.

Note: I am using the ballot preference above as an example. It aligns with my views at the moment, but things might change. Please don’t judge me too harshly if you have other opinions.