Why a hung Parliament is a good bet
Take a look at the following chart:
It shows the number of MPs elected at each election who were not Labour or Conservative, or allied with the two major parties (in the way most Northern Irish MPs used to be).
So in 1959 there were just six Liberal MPs and one Independent.
Over the years this "others" figure has crept up pretty steadily, to reach 87 MPs at the last election, and 93 MPs now after by-elections, expulsions and defections. (I exclude the Sinn Fein MPs from all these figures, as they never attend the Commons, as well as the Speaker and his three deputies.)
The growth reflects several trends:
First, the revival of the Liberal Party and their successors, the Liberal Democrats, from a mere six MPs in 1959 to 62 in 2005 (and 63 now).
Then there was the dramatic arrival of Scottish and Welsh Nationalist MPs in the 1970s, with a total today of 10 SNP or Plaid Cymru members in the House (though the figure has been even higher in the past).
Third, the number of Irish MPs has grown from just 12 in the decades after the war, to 18 today. What's more, until the early 1970s, most of them, the Official Unionists, were allied with the Conservatives, whereas nowadays the Democratic Unionists are independent.
And finally there's been a small growth in the number of independent MPs (such as Richard Taylor and Dai Davies) and MPs from minor parties, such as George Galloway of Respect, and Bob Spink of UKIP.
This growth of what one might call a balance-of-power block means that it's now a lot harder for one of the two major parties to win a general election outright. In the 1959 and 1964 elections Labour or the Tories only needed ten more seats than their rivals to be sure of a majority in the Commons.
Forty years on, the figure is almost 100. It's a remarkable feature that in 17 elections since the war, only once, in February 1974, have we ended up with a hung Parliament.
Statistically one would expect it to happen a lot more often, especially with the growth of minor parties outlined above. Indeed, some people suspect that the British electorate senses the problems of a hung Parliament and gives a last-minute nudge to the likely winner. (A similar phenomenon seems to occur in English football where it's surprisingly rare for the league to be won on goal difference.)
Certainly many leading Conservatives expect that outcome in 2010. They think its simply too big a task, in one election, to gain the 116 seats they need for a majority, on what would require the second biggest swing in 60 years. Instead, they think their best bet is to be the biggest party in a hung Parliament with the chance of winning an outright majority in a second election in a year or two. It's the two election strategy.
Equally, many Labour people are consoling themselves with the thought they might hold onto power through a hung Parliament.
And even if it doesn't happen in 2010, it bound to happen before long.