The idea being that, instead of getting slanted leaflets coming through your door distorting the facts of what AV is, and what voting Yes or No would lead to, you'd just get a simple description of the two systems.
That way you'd just make up your own mind without being cajoled by party loyalty and celebrity endorsements.
So, here is a nice, uncomplicated description of what AV is and what First Past the Post is.
Alternative Vote (AV) - YES
To vote, you rank the candidates in order of preference, with "1" signifying your first choice and "2" your second, etc.
If, after all of the votes are counted, there is a candidate with "1s" from more than 50% of the electorate, then they win.
If not, the candidate with the lowest number of "1s" is knocked out of the process and the second preferences ("2s") of their voters are distributed amongst the remaining candidates.
If then there is a candidate with 50% of the vote, they win. If not, the above process is repeated until there is a winner (a candidate with 50% + of the vote)
In practice this means that you, the voter, can vote for not only your favourite party, but also for a second and even a third choice.
First Past the Post (FPP)- NO
You tick the box for the candidate that you like the best.
The candidate with the most votes wins.
(Above is as objective as I can be, below is opinion)
So, as you can see, FPP is a lot simpler to explain. However, it has been known to cause problems that are not simple in practice.
In a situation where there are two parties with similar agendas which share by far the majority of the vote, but a third party wins while representing, in essence, a minority opinion, democracy has not really been served, in my opinion.
So, imagine a constituency where 33% vote for the Greens, 31% vote for the Hippies and 34% vote for the Globalwarming Is a Myth Party with 2% voting for the Vegans Ask God party.
In an FPP election, GIMP win, despite representing a minority opinion. In an AV election, the Greens would win, as they represent a more broad sweep of the electorate. The VAG party's 2% would be evenly divided between the Hippies and the Greens, then the Hippie vote would presumably go to the Greens leaving the result as Greens with 66% and GIMP with 34%.
The Hippies and the VAG would combine to screw the GIMP, turning the seat Green.
My finest hour? Perhaps not.
But anyway, if you have not understood what we're voting about tomorrow, I hope this has somewhat demystified the whole thing a bit.
AV is not complicated - voting in AV just means that you rank the candidates that you like 1,2,3 until you don't want to show anymore preferences. FPP gives you one 'X' on the candidate you like the best/think will represent your views best amongst the field of those likely to win/might beat the guy you really don't want to win. Vote YES for AV and vote NO for FPP.