Friday, July 24, 2009

The slow death (by pie) of Labour and Tory Britain

Mark Reckons looks at the long-term decline in the share of the vote going to the two main parties, which has dropped from around 90% in the 1950s and 1960s to around 70% in the last couple of elections. He notes that (for the time being at least) the first-past-the-post voting system is keeping their overwhelming dominance in Parliament.

I would say that we are becoming increasingly pluralistic as an electorate. We have got used to voting for smaller parties and those often described as "others". I think the vote share of the two main parties will continue to decline and it will get harder and harder for them to justify the present system.

Mark’s post is titled ‘How low can we go?’, and I couldn’t resist thinking about an answer. What follows, as Peter Snow used to say, is just a bit of fun.

For reference, the 2005 election result:

C 33% (198 seats), L 36% (356), LD 23% (62), Others 8% (30)

Now, the latest Populus poll seems a fair place to start; feeding that into the seat calculator at Electoral Calculus, we get:

C 38% (341), L 26% (222), LD 20% (56), Oth 16% (31)

So despite a doubling of the minor parties’ vote, their seat tally is basically unchanged.

What I did next was gradually shift support away from the two main parties and towards the Lib Dems and others. I’ve taken a series of steps, each subtracting 1.5% from the Conservative vote and 1% from Labour and adding 1% to the Lib Dems and 1.5% to the others.

The result is s series of pie charts. The headings give the vote shares and the sizes of the slices show the number of MPs returned; the Conservatives are blue, Labour red, Lib Dems yellow and others green.

So, as the Labour/Tory vote erodes, the Lib Dems scoop up more and more seats, but the other parties hardly make headway, even at a quarter of the vote. And even when the Labour/Tory vote dips to 49%, they still hold just over three-quarters of the seats in parliament.

But then we reach what looks like a tipping point:

The Lib Dems continues their forward march (although even on becoming the most popular party, they still lag third in terms of seats), but now the minor parties really start to make advances as well.

From here on, the results splinter in all directions, and we can clearly say that even the three-party system is no more:

But of course this wouldn’t really happen, even if such mammoth shifts in votes did take place. There’d be massive local variation, and different minor parties would do well in different areas and against different main parties. But it’s an intriguing bit of Friday fun.

And now all this talk of pie has made me hungry...


Mark Reckons said...

Fantastic analysis!

Of course you are correct that in reality it wouldn't happen exactly like this but is is fascinating to see the extrapolation of the positions and to see only 49% of the combined vote still yielding around 75% of the seats is a damning indictment of the distortion of FPTP.

I will link to this blog post from the original article.

Eunoia said...

Very interesting post. Thankyou.

Have to try it out on different voting systems, when I get the time.

lifeonmars said...

The situation is actually worse than you suggest. The 70% figure you give refers to the share of THOSE WHO VOTED. When you take into account the low turnout – presumably many of those who did not vote had decided that their vote wouldn’t count anyway – fewer than 50% voted for either of the two main parties. Barely one in five of us endorsed the current government – yet they were returned with 55% of the seats.

The Tories are currently crowing at their recent by-election result – in which 18% of the electorate voted Conservative (Labour limped home with 8.5%). Even allowing for the fact that by-elections suffer from low turnouts (in this case 45.9%), it’s quite an indictment of the system when a party can claim legitimacy on a fifth of the potential vote.

Indeed, the whole of our political discourse is filtered through the prism of FPTP – giving us a kind of virtual reality politics in which Margaret Thatcher receives ‘landslide’ majorities although never achieving more than a third of the electorate’s votes - 33% in 1979; 31% in ’83; 32% in ’87.

The whole our political history has been distorted by a cranky electoral system in the name of providing ‘strong’ government by those who argue that it is better to have one party rule than a weedy consensus. Looking at the wreckage of the past 20 years, that seems less and less persuasive.

Of course, we don't know how a different electoral system would affect voting patterns.