The alternatives are clear

Looking at the debate brewing in Britain right now over the  "Alternative Vote",  I don't know whether to laugh or cry.  It's utterly astonishing how much confusion they are generating over what seems an incredibly simple issue.  Okay,  I have the benefit of having lived most of my life in a country that uses this system and am therefore not beset by any of that fear of the unknown that evidently plagues so many Brits when faced with it,  but it still seems to be causing them far more trouble than it warrants.

Basically the proposed reform is to replace their current,  dreadfully undemocratic first-past-the-post voting system with one allowing people to vote for the candidates in order of preference,  voting  "1"  for the candidate they like most,  "2"  for their next favourite,  and so forth.  Candidates with the fewest votes are eliminated and their voters'  next preferences are counted until one candidate gets 50% of the total votes cast.  All fairly straightforward,  surely.

The pro and contra sides of the debate,  however,  have managed to befuddle things magnificently,  partly through deliberate misinformation and distortion of the truth,  but perhaps partly through a sheer inability to communicate clearly.

Essentially,  it all boils down to this:

Currently,  British voters mostly vote for either the Conservative Party,  which gets about 30-40%  of all votes across the country,  the Labour Party,  which also gets about 30-40%  of all votes,  or the Liberal Democrats,  who usually get about 15-20%  of all votes.  Under the first-past-the-post system,  it is entirely possible for either the Conservatives or Labour to win a comfortable majority of seats in the House of Commons on these figures,  while the Liberal Democrats struggle to win a handful.  The winner of each seat is elected by a geographically defined  "constituency"  of voters,  with these three major parties all fielding candidates in most of the them.

The other important fact to know when assessing the potential impact of the  "Alternative Vote"  is that opinion polls have fairly consistently indicated that people who vote Liberal Democrat prefer the Labour Party to the Conservatives by a ratio of at least 2 to 1.

What that means is that when the Conservative candidate and the Labour candidate come first and second in the race for a constituency,  causing the Liberal Democrat candidate to be eliminated,  the next preferences of the Liberal Democrat voters would favour the Labour candidate heavily.  Labour should end up with at least two thirds of the Lib Dems's 15-20%  of the vote. Labour should also pick up preferences from Green voters and voters for various other small left-wing parties,  totalling a further 2%  or so of the vote.  As for the Conservatives,  all they can really rely on,  apart from the remaining third from the Lib Dems,  is the preferences of UKIP and BNP voters  -  about 5%  nationwide.  This will give Labour a major advantage in many seats and should cut heavily into the Conservative representation in parliament.

In constituencies where Liberal Democrat candidates currently comes first or second,  they will probably be the greatest beneficiary,  as they will presumably pick up preferences from both Labour and Conservative voters.  So the Lib Dems will win seats from both the other major parties.  At this point it's important to remember that there are not in fact very many seats  (relatively speaking)  where the Liberal Democrats come first or second,  which will seriously limit their potential gain from the Alternative Vote system.

Result:  number of Conservative seats falls a lot  (as they will lose them to both Labour and the Lib Dems);  number of Lib Dems seats rises but by a much smaller amount,  and the Labour Party probably stays at about the same level it is at now.  And that means,  in turn,  that Labour could still find itself with an outright majority in the House of Commons,  but the Conservatives will quite possibly never enjoy that position again  -  unless and until they shift their politics towards the centre,  i.e.  towards the left.

This is the simple,  sufficient and only reason why nearly all of the Conservative Party is against the proposed reform,  while most of the Labour politicians,  and all of the Liberal Democrats,  are in favour.

A lot of the distortion of the truth coming from both sides in the debate is,  I am certain,  the result of their attempts to avoid saying how the reform will affect them personally.  Neither the Conservatives nor the Liberal Democrats nor even Labour can admit that their main concern is what it will do to their numbers in parliament,  so they come out with whatever other spurious arguments they can dream up.  I really wish they could just come clean and tell people straight up:  "If you like the Conservatives,  vote against it.  If you hate them and/or like Labour or the Liberal Democrats,  vote for it.  That's all there is to it,  folks."