What hasn’t been often highlighted so far in the debate about the Alternative Vote (AV), is that many groups working on behalf of some of the most vulnerable and disempowered people are backing the Alternative Vote, because they recognise the benefits that it could bring to those with whom they work (and not just in the UK).
From the World Development Movement, seeking justice for the world’s poor, to Operation Black Vote, and the Community Sector Coalition, Urban Forum and bassac, these organisations  support often vulnerable or disempowered communities to have a greater say over decisions that affect them.
Many of these groups believe that the people they seek to help will benefit from the Alternative Vote system because it will widen the political debate in the UK to a greater range of issues that often don't make it onto the agenda during elections. Candidates will have to appeal much more widely, beyond their core vote in order to get elected, and so issues such as debt in the developing world, overseas aid, climate change, as well as others which directly affect some of the most vulnerable in the UK, may be given greater priority. This is a view reflected by the membership of groups like Greenpeace and Friends of the Earth in the "yes" campaign, too.
But not only might the concerns of such groups more readily make it onto the political agenda as MPs have to appeal more widely for preference votes, but AV will also begin to challenge the correlation between safe seats, low voter turnout and social deprivation. AV changes the psychology of voters  who will vote differently. Turnouts may rise. Parties who have neglected constituencies may suddenly realise that a majority of constituents in fact oppose them, and lose their seats.
As Democratic Audit  noted at the time of the 2010 election:
“There is an increasingly obvious relationship between political inequality and other forms of inequality. Almost two-thirds of seats with turnouts below 50 per cent in 2005 had ‘worklessness’ levels of 25 per cent of more”.
They also suggest that this is an area which has been overlooked in the political debate about electoral reform itself:
“There has been remarkable reluctance, not just among the main two political parties, to debate the role of the electoral system as a factor prompting low turnouts, or to discuss the wider implications of all the political parties targeting their efforts at a minority of seats. But this is no longer just a question of political participation. That many of the seats in which local democratic activism and engagement (whether measured by campaigning, spending or voter turnout) are lowest also suffer the highest levels of social deprivation is perhaps the greatest indictment of all against our current electoral system.”
It is also relevant to note who it is that is opposing the change in our electoral system. In a letter in the Independent newspaper earlier this month , Elliot Folan perceptively notes:
“Your report and leading article (29, 30 December) reinforces what is becoming clearer as we move closer to this referendum on voting reform, that it is the status quo of left and right (right wing newspapers, trade unions, politicians, big business) who are gathering in an unholy alliance for a “No” vote because it suits them to keep politicians unaccountable and in their control. Yet it is ordinary people – many from no party at all – who are uniting behind a “Yes” vote.
“It should not be a surprise to anyone that two large unions are planning to join the “No” campaign. It suits the unions to keep Labour in their pocket, which they can do under our broken system but which would be harder under a more democratic system such as the Alternative Vote.
“When only a few thousand voters in marginal seats decide a government, union cash can swing an election. When nearly every seat is marginal, all that matters is what parties stand for. That is how democracy should work.
“That the GMB and Unite have apparently declined to consult their members on this huge decision shows that the union leadership is still cut off from the people it claims to represent. Unions, for all the important role they play in society, are turning their back on the single greatest reform to the Commons since women were given the vote. As you say, they are showing their regressive side.”
The experience of the US where a new city has adopted AV (known by its other name “instant runoff”) every year since November 2004, suggests that AV can play a very important role  in challenging the power of big money, and other vested interests, whilst empowering those often left without a voice to have one. (See also here )
Update:18.16 Thanks to @DPJHodges who drew my attention to the fact that the argument above could have been clearer. Third paragraph has been re-written to reflect this.
Update: 31/01/11 Stephen Doughty, Former Special Adviser to the Secretary of State for International Development, has now written about how AV could affect the agenda for the developing world here: http://lcid.org.uk/2011/01/30/could-av-mean-a-fairer-deal-for-the-worlds-poor/ 
This is the third in a series of posts exploring different aspects of AV