In recent weeks there’s been a positivity about the Tories’ chances of winning outright in 2015, Michael Gove was reported to be convinced of that, and over at Betfair, the implied probability of a Tory majority has been increasing in recent weeks (though there has been an easing back from the recent high point)

But looking at the table below, which shows the the change of the share of the vote at the election between the governing party and the principal opposition party from the previous election. The figures in red and brackets indicate a decrease in share of the vote, figures in black indicate an increase in the share of the vote.

Year	Govt	Opposition
1959	(0.30)	(2.60)
1964	(6.00)	0.20
1966	3.90	(1.50)
1970	(4.90)	4.50
1974 Feb	(8.50)	(5.90)
1974 Oct	2.00	(2.10)
1979	(2.30)	8.10
1983	(1.50)	(9.30)
1987	(0.20)	3.20
1992	(0.30)	3.60
1997	(11.20)	8.80
2001	(2.50)	1.00
2005	(5.50)	0.70
2010	(6.20)	3.70

In the last fifty-four years, only two governments have seen their share of the vote increase,and the last of those occasions was thirty-nine years ago. Both of these were in circumstances, not available to David Cameron and the Conservatives. Harold Wilson oversaw both increases, the 1966 election was held 2 years after the previous election, and the October 1974 General election was held eight months after the previous election.

If as a Government, you’re going to increase your share of the vote, the only way is to hold the election shortly after the previous election, and not to go the full four/five year term, in hindsight Dave may regret not holding a second election in 2010.

In the same timeframe, only five oppositions have seen their share of the vote decline from the previous election, Harold Wilson to compliment his increases in government, oversaw a decline in the oppositions votes

Two of these declines happened under Edward Heath, someone who lost three out of the four general elections he fought as Tory Leader, one of the five happened under the man considered the worst Leader of the Opposition, Michael Foot in 1983, and the last time an opposition decreased their share of the vote, that happened in part because of the formation of the SDP. The other two occasions were in 1959 and February 1974, which could be down to the re-emergence of the Liberal Party.

The caveats of this analysis, this is a coalition government, none of the governments in the above table were coalitions,and governments have increased the number of the seats despite a decrease in share of the vote, but that was when the principal opposition party also saw a decrease in their share of the vote, given the movement of a significant chunk of the 2010 Lib Dems to Labour the moment the coalition was created, that also seems unlikely.

In Scotland, in 2011, The SNP saw their vote increase in both the constituency and the list, so there is a recent precedent for Dave, but as with so many other things, Scotland is very different to the rest of the UK.

Overall, this analysis makes me think, if you’re not already laying a Tory majority, you should be doing so, their share of the vote will not be going up and Labour’s won’t be decreasing if recent history repeats itself, a Tory majority seems a remote prospect, even without the electoral system favouring Labour.

No wonder Dave is planning for a second coalition rather than planning for an outright majority.

TSE