How STV would re-enfranchise voters

With all the discussion there has been in the last few weeks about potential electoral reform, I have found myself discussing and debating the issues surrounding this in various media.

I was having a discussion with someone on Twitter about this last night. He is a Conservative supporter who lives in the Manchester Withington constituency. Currently his MP is Liberal Democrat John Leech and he is not happy about this. I tried to explain how STV would help to re-enfranchise him but 140 characters is not the STV advocate's friend so I have had a look at the numbers and will try and explain what I mean here.

Single Transferable Vote works with multi-member constituencies. In the case of Manchester Withington, here are the figures for the last General Election in 2005 when the seat was last contested:

General Election 2005: Manchester, Withington
Party		Candidate	Votes	%	±%
	Liberal Democrat	John Leech	15,872	42.4	+20.4
	Labour	Keith Bradley	15,205	40.6	-14.3
	Conservative	Karen Bradley	3,919	10.5	-4.8
	Green	Brian Candeland	1,595	4.3	-0.1
	UK Independence	Robert Gutfreund-Walmsley	424	1.1	+1.1
	Independent	Ivan Benett	243	0.6	+0.6
	Independent	Yasmin Zalzala	153	0.4	+0.4
	Their Party	Richard Reed	47	0.1	+0.1
Majority			667	1.8
Turnout			37,458	55.3	+3.4
	Liberal Democrat gain from Labour		Swing	+17.3

So there were just shy of 4,000 votes for the Tories on a turnout of 37,458 meaning a vote share of about 10.5%. Under FPTP it looks very unlikely that my friend will find himself represented by a Tory after the next election. Indeed he was talking about perhaps voting tactically for Labour to get Mr Leech out (this was under a hypothetical AV system we were discussing which shows that AV does not stop tactical voting and which further disenfranchises people, anyway I digress).

I then had a look at this page on Wikipedia which shows the Greater Manchester constituencies and had a quick look at how an STV 5 member constituency could be created. I plumped for a merging of Manchester Withington, Wythenshawe and Sale East, Cheadle, Hazel Grove and Stockport. These are all contiguous and would make up a reasonable 5 member constituency I think.

I won't list all the data from these seats but the salient information (taken from the 2005 election results) for this exercise is:

The way that seats are calculated using STV is a little bit more involved than just a straight percentage read-across however if the 2005 election in these seats had been run as STV it is fair to assume that the Conservatives would have got about 25% of first preferences. We cannot know for sure due to second third and so on preferences but it is likely that the Tories would have got one MP under such a system (as 5 members would be elected here and 25% should give them one of those) whereas at the moment they have no MPs in any of these seats.

This would enfranchise my friend in Manchester Withington whose vote would have counted for something in the 2005 election.

Perhaps Conservatives should bear all of this in mind when they are discussing electoral reform in the future and not just dismiss it out of hand. "PR" covers many systems but STV is the fairest one that gives rough proportionality and still maintains good (some would say better than under FPTP) constituency links.