#VoteBike - 2012 London Mayoral elections

On preferences and so on, I voted Ken to try and keep Boris out, very much through gritted teeth. Anyone who voted Green, Independent or anything other than Ken as first preference helped Boris get back in

I'm sorry, but I have to pull you up on this single statement.

I've done a lot of looking at this over this campaign, and this statement is one of the biggest misnomers from those who do not truly understand the voting system.

You have read the full details of it on London Elects haven't you?

The system that the Mayoral elections are run on is the 'Supplementary Vote' system. Counting works like this:

If a candidate receives more than half of all the first choice votes they are elected immediately. If this does not happen, the top two candidates with the most first choice votes go through to a second round. All other candidates are eliminated, but the second choice votes on their ballot papers are calculated. Second choice votes for either of the top two candidates are added to the totals for those two candidates from the first round.

The candidate with the highest combined total of first and second choice votes will be elected as Mayor of London

That's direct from the London Elects site.

This actually means that anyone who didn't vote for Boris in the first round helped stop him getting in, unless their second preference was for Boris. If their second preference was for Ken, they helped stop Boris getting in. If they voted $notKenorBoris then $notKenorBoris they helped force it to the second round, but didn't change the final outcome.

Failing to understand the voting system is understandable, the ones used for this are rather opaque*, but if you can do the maths, easy to work out and understand, but your maths comprehension does need to be good. If you haven't bothered to look into it properly and understand it, don't pass on your incorrect knowledge, it only makes things worse.

*At one point, I found myself in the fun position of having to explain the way that the assembly voting worked to the green party (via a third party), they had got it wrong, that's how tricky it is.

TL;DR? Go back and do so. It's important you know how your vote counts.