Over the past few days a lot of "lessons" have been drawn from the Eastleigh byelection. Most are of no fundamental importance. The key fact is that the crushing defeat of the Tories is simply part of the trend of Tory electoral decline. This analysis also enables us to predict that the Tory party will get 30.3% of the vote at the next general election. The aim of this article is to explain why.
The continuing decline of the Tory vote from 1931 to 2010 is shown in the graphic left. This demonstrates clearly that while there have been short-term oscillations from election to election, which help to produce individual Tory victories or defeats, the steady downward trend of support for the Conservative party is evident. In 1983, when I first demonstrated this decline, it was greeted with widespread scepticism. But 30 years later it is evident.
Typically, the Conservative vote, each time the party won a general election, was lower than the one it won previously, and each time it lost an election its vote fell to a lower level than the previous defeat.
The result of the Tories at the 2010 election, at 36.1% of the vote, is 5.8% below the level they received the last time they were the largest party in 1992. In victory, the Conservative vote has fallen progressively from its highest level to date, of 55% in 1931, to a post-second world war peak of 49.6% in 1955, to 41.9% the last time it won a majority of seats in an election in 1992, to 36.1% in 2010.
The decline in the Tory vote can be calculated from a rather simple arithmetic formula. The Tory vote declines at 0.2% a year. There is a swing factor of slightly under 5% between defeat and victory.
Behind this arithmetic is of course a social process – the progressive collapse of the Tory party back into its south-east England heartland. The Tories have declined from a "one nation" to a "half a country" party.
Taking these projections, if the Tories won the next election, they would get 34.6% of the vote, and if they lost they would get 30.3% of the vote. As there is no doubt at present that the Tories will lose, they will get 30.3% of the vote. As always there is a bit of statistical noise in any calculation, so 29.3% to 31.3% would be a reasonable range, but 30.3% is the central figure.
The conclusion is evident. Even at 34.6%, the Tories would not win an overall majority, and at 30.3% they will be crushed. Naturally Labour must show at least reasonable competence to win. In addition to its public performance, I know from negotiating with Ed Miliband several times when working for Ken Livingstone when he was mayor of London that this will occur.
The really big choice in British politics is this: what will be the policies of the next Labour government? Not what will be the outcome of the next general election. That is already determined by force far more powerful than the Eastleigh byelection.